You guys may wanna check this out. BrandonBaskin an XDA member had a OTA notification popup on his Vivid, he uploaded it, and the devs created a working CWM flashable stock AT&T ROM. I've had it on mine since yesterday, and it's a pretty sweet upgrade! A few people have had issues getting it working, but I think most got it working at some point. FYI it's ICS 4.03 with Sense 3.6.
ROM Thread: [FIRMWARE] [ICS] [4.0.3] STOCK & Rooted (3-3-2012) - xda-developers
Original OTA thread: Vivid ics ota update! 3/3/2012 - xda-developers
ROM Thread: [FIRMWARE] [ICS] [4.0.3] STOCK & Rooted (3-3-2012) - xda-developers
Original OTA thread: Vivid ics ota update! 3/3/2012 - xda-developers