Interesting - Vibrant ROM on Captivate
Day 1 - Rooted my phone successfully
Day 2 - Hosed it up royally with a bad metamorph attempt at changing the fremework-res items (endless stream of FC's at startup, no icons, no menus, no adb access)
Since I couldn't find an original ROM for the Captivate, I started messing with the Vibrant ROM files from MS_Guru's post on the Vibrant forums
Using Odin and the combination of the Vibrant .pit file and the T959-PDA.tar file (Didn't flash the CSC or Phone tar's figuring they were tied to the hardware and not the ROM) I got it running again!
I haven't played with it to see just how much functionality is missing using a T-Mobile ROM on AT&T, but the phone (3G even), wifi, and standard stuff seems to work just fine.
I definately don't suggest
doing this as a ROM replacement, but as my phone was useless prior to I figured what the heck!