Popular? Maybe. Major? Nope.Well, seeing as how Bahamut is Level 36, the bar has already been raised. I anticipate that Lolth will also be Level 36. She is a major (ie. popular) evil power.
IIRC, they even mentioned in the preview articles for 4E that major deities like Moradin would probably be level 36. I don't expect anything to ever have a higher level.
I do think, btw. that 4e still has too few level 30+ (or even level 26+) 'monsters' to pick from. I really wouldn't want to run an epic level campaign right now (but then again I'm not a fan of epic level gameplay, anyway).