Hi Doug -
Yep, there are quite a few db schema similarities between the two products. There isn't currently an automated upgrade process from forums/integrated to clearspace, but there will be. It will be in clearspace 1.1 (a release for which we are still working on a date, but we're expecting it to be in the first half of this year.)
I don't know if I can wait that long. What I'm most concerned about is users. I don't mind writing a perl script to migrate the existing users from Integrated to Clearspace, I've got >100. I just need to know what tables hold user data.