Hi, I'm the non-JW half of a mixed marriage. You can do anything you like as long as you are independent and living on your own. The trick is not in what you can do, but what you are willing to do, weighing your options.
This belief of not dating anyone who isnt a witness...is there anyway around it?
Sure, do it anyways and get married privately. What can they do?
Well, they can do a few things. They can "mark" you and informally shun you. So do weigh the balance on how valuable this person is to you. There are some wonderful, quality people out there. So don't think this is an easy answer. Sometimes it is worth it to marry a person of great character in spite of everyone's opinion. Such people are rare indeed, you may never come across a flower so perfect again in your lifetime.
anyway short of converting them?
I have a problem with putting ultimatums and conditions on the person you want to marry. I don't think you show much value for the person when you do that. What does your loved-one say about this?
Because the person is truly great, but parents have forbidden us from seeing each other.
Do you live at home? Then you are stuck. Otherwise, you do have the freedom to make your own plans, counting the cost of course.