It's not official but one of the cast members (Grizz) tweeted today that 30 Rock has been renewed for next season:

https://twitter.com/#!/grizz30rock

Grizz chapman ‏ @Grizz30rock
30 rock picked up for a 7th season ... Nahhh ... YEAHHHHHH

Considering this is when NBC usually renews their comedies, maybe we'll see official confirmation soon? And maybe renewals for some of the other comedies as well?

I hope he's right, but this is NBC we are talking about and anything can happen. I do think they will renew for a mid season placement and it will most likely be the last.

i think it will be back - but with more of the classic NBC scheduling nonsense and a long hiatus

I think it'll definitely be back. How long or when it'll be back might depend on how it does at 8:30 these next few weeks. If it can stay around the 2.0 it got last week then I don't see any reason why they should get a shortened season. But then again, like you said - this is NBC, and they ordered a lot of comedy pilots next season. Plus The Office, Parks & Rec, Community, maybe Up All Night & possibly even Whitney will be back next season. Guess we'll see.

Whatever NBC does, they should move their comedy block from Thursdays. With CBS probably expanding to 2 hours, its time to (sadly) admit Thursdays aren't your night anymore. I say this with a heavy heart because I love the NBC Thursday night tradition, but last week proved these shows could do significantly better without competition. Either that or just accept the small audience that it still watching these shows on Thursday nights.