simon: it does locking
http://www.bitbybit.dk/mysqlfaq/changes.html?gr=Concept&keyword=Locking
if you don't like mysql, there's also other alternatives like postgresql and borland interbase
also, about modifying the OS, you'd be surprised how many people do it. There's a mailing list for kernel development, and even though there's still a lot of kernel hackers not subscribed to it, the daily digest of the mailist list is always over a megabyte.
if you still don't believe me, here's 60 pages of modifications individual people have made the the OS...and this is by all means not an exhaustive list.
http://kernelnewbies.org/patches/
SYN: just curious, but do you visit somethingawful.com a lot? your post made me think of jeff k :p