Running Stock Froyo/Gingerbread on Thunderbolt

Is it possible to port over and use 2.3.3 or other stock iteration of Android?

Yes. It will take a chef with more talent than me to do it, but give it time and someone (Most likely the Cyanogen Mod Team) will have a port ready that runs smooth on this phone. I'd bet my first born on it...
 
CM7 is already running on the Inspire, so we won't be too far behind. I'll try out Sense for a while, but I'll end up with some variant of CM for sure.