Hey rygel411, does this sound like your situation?
1) Boot phone up fresh full reboot
2) Phone grabs a 3g/4g signal instantly and holds it for several hours fine
3) Randomly when you power on the display, you are missing a 3g/4g icon but have full bars
4) Checking under Wireless Network settings, Mobile Networks is OFF and WON'T turn on
5) Reboot solves the problem or Wait approx 2-4 hours and it solves itself randomly without doing anything
Does this sound like your situation? No 3g/4g icons and no data connection, and unable to turn data back on without a reboot or waiting a long time? Cuz if so this is exactly what happens to me and I live in central NJ. I always get perfect 3G signal on all my phones, even in my house. And my data speeds are generally good; 1500-3000kbps on 3G.
I am running MR2 Das BAMF Gingerstripped with Imoseyon's 3.4.0 GB Kernel. It IS related to Gingerbread, as my girlfriends Thunderbolt running full stock does not see this issue at all.