It may be possible to bridge the databases. But this depends on how the registration information is stored and retrieved in the chat script.
It's possible. I even know how to do it.
But after thinking about it, I probably won't bridge the two. This way we are not forcing the chat people to make a forum account. Also when you deal with databases, there's always a risk of monumental failure. I just don't see the point in risking it because the current system works just fine.
Identity theft is not a problem because of IP addresses. And frankly, I find it very unlikely that we would have tons of people trying to be Bloodshadow in chat.