No custom ROMs until we unlock NAND.
Even if/when we do, porting Sense to a Motorola product has proven to be difficult, as was the case on the original Droid.
That being said, IMO, Sense is clunky, overrated, and a memory hog. It offers some nice integration, but nothing that can't be done better with 3rd party apps.
Droid X + LauncherPro/ADW + Beautiful Widgets is basically Sense without the bloat.