Abaddon, I'll try to deal with your question, it may take a few posts though. I'll try to consolidate them if I am within the edit time. I know that your question referrs to other accounts besides Matthew, however I'll first deal with the dating of Matthew since the dating is relevant to the time of Matthew 27:53 as well as the fact that the jesusneverexisted.com "date" of Matthew makes it to old to have been written by Matthew himself.
Was Matthew written close to the time of the events that it describes?
Regarding Matthew, the jesusneverexisted.com site says:
A Greek-speaking Jew, writing in the pagan city of Antioch shortly after the riots of 117 C.E. had convulsed Palestine and the diaspora was at pains to reassure the Roman state that his particular creed posed no threat to the imperium. The writer, a follower of the Rabbi Saul, having fled 'fundamentalist' Jerusalem for the relatively enlightened pagan city of Antioch, took a copy of 'Mark' as the basis for his own ‘story’ and concocted what would eventually become known as 'Matthew.'
Many scholars (conservative and liberal) date Matthew before the fall of Jerusalem in AD 70. It was sited by two early writers that I am aware of, both who lived prior to the date of "after . . . 117 CE" given as the date of Matthew by the above site.
Clement of Rome (A.D. 95) who quoted from: Matthew, Mark, Luke, Acts, 1 Corinthians, Titus, Hebrews, and 1 Peter The New Evidence That Demands A Verdict p. 44
Ignatius (A.D. 70-110) who quoted from: Matthew, John, Acts, Romans, 1Corinthians, Galatians, Ephesians, Philippians, Collossians, 1 and 2 Thessalonians, 1 and 2 Timothy, James, and 1 Peter The New Evidence That Demands A Verdict p. 44
Halley's Bible Handbook also states that both Clement of Rome and Ignatius quoted from or alluded to Matthew, as well as the dates of their references being A.D. 95 and A.D. 110 respectively.
Also early church tradition teaches that Matthew was the first Gospel written, and that it was indeed written by Matthew, hense for some one to claim that someone other than Matthew wrote it, and that it was written at a late date (as the above site does), is to dismiss primary evidence in favor of speculation based on no primary evidence.
Conclusion: There is plenty of evidence to show that the gospel of Matthew was early and hense close to the time of the events that matthew 27:50-54 described. I'll now move on to a discussion of the verse in question, then later on to your point about other contemporary accounts.
 Jesus, when he had cried again with a loud voice, yielded up the ghost.
 And, behold, the veil of the temple was rent in twain from the top to the bottom; and the earth did quake, and the rocks rent;
 And the graves were opened; and many bodies of the saints which slept arose,
 And came out of the graves after his resurrection, and went into the holy city, and appeared unto many.
 Now when the centurion, and they that were with him, watching Jesus, saw the earthquake, and those things that were done, they feared greatly, saying, Truly this was the Son of God.
Abaddon said: Also, as is traditional in these discussions, I must ask you why there is no corroberation from contemporary accounts of the dead rising when Jesus was ressurected and going around preaching. People might have noticed this. Even if they weren't dancing to 'Thriller' at the time, people would have probably made some note of large numbers of dead people wandering around.
Nowhere does the text directly state that these resurrected individuals went "around preaching", the text simply states that they "appeared unto many." Nor does the text say how long they remained. It is also important to realize that the resurrection from the dead is also a restoration of the body that died. Hense these people would not not necessarily look half-rotten or goulish. They would simply be recognized as people who had died and who now were appearing to many. So the event may not have been as dramatic as it is often portrayed.
Other Contemporary Accounts?
These types of resurrection people (probably in normal form, like Lazarus was raised) form the basis for one argument of the first apologists of the faith, Quadratus. He was an very early 2nd century apologist (writing sometime during the reign of Hadrian, 117-138ad), and we have only one fragment of his (cited from GASC:36):
"But our Savior's works were permanent, for they were real. Those who had been cured or rose from the dead not only appeared to be cured or raised but were permanent, not only during our Savior's stay on earth, but also after his departure. They remained for a considerable period, so that some of them even reached our times."
Now it would be highly unusual for someone raised in 33 ad to live naturally another 90-100 years (to the times of Quadratus' writings) but this is not necessarily the scope of his reference to 'our times'...this latter phrase could often mean plus-or-minus 50-75 years, allowing SOME of these saints to die naturally again (as would have the resurrected Lazarus, the widow's son, etc.) after a few decades.
The point is that resurrections are not isolated phenomena--they were a bit more widespread than the few individual cases mentioned in the gospels would lead us to believe...Eutychus by Paul, the group at the Crucifixion--indeed, even Ireneaus--a half century later--could write of resurrections in Christian Churches (A.H. 2.32.4)...
Indeed, stories and legends of these risen saints circulated and were embellished over time. They show up in several of the NT apocryphal works (e.g. The Greek Apocalypse of Ezra 7.1-2, Gospel of Nicodemus 17ff). For example, in this later work (Gospel of Nicodemus/Acts of Pilate), there is the story of Simeon and his sons (living in Arimathea), who were raised at that time, whose tombs were still open (for inspection!), and who wrote sworn testimony to their resurrection. While many of these stories are no doubt fanciful embellishments of the passage in Matthew (apocryphal writings generally "filled in the gaps" left by the biblical writers), there may be some historical core behind such related stories as this one about Simeon.
So far the closest (date wise) account to the one in Matthew that I have found is the account given by Quadratus (which is also printed in The New Evidence That Demands A Verdict). The account might be related to the resurrection in Matthew, or to others who were resurrected by Jesus before his crucifixion. While the account by Quadratus is much later than the events described in Matthew, the fact that he referrs to "some that even reached into our times" seems to give his writings some relevance.
Since first century historical accounts are limited to what extent would one expect to find evidence from other historical sources about such an event? Such an event probably would not have been included in secular histories. The only sources that I can think of that might be expected to possibly contain such an account would be those sources which wrote detailed histories of Jerusalem. How many first century writers wrote detailed histories about Jerusalem? Josephus comes to mind, but does anyone else? My knowledge of first century historical sources is limited, so if anyone can think of another source which should reasonably have included the account in Matthew 27 please list it. Otherwise the issue may simply be why did Josephus who wrote first century historical accounts of Jerusalem not give a contemporary account of Matthew 27:53 if such an event really occurred?