I'd limp expecting a short stack to go allin...

With the blinds as high as they are, it become all or nothing for almost half your table...If somebody goes AI to your left and somebody else calls, I would dump the hand unless it's another SS. If somebody goes all in to your right, I would reraise to isolate. Your hand is probably better then the majority of hands that the short stacks will go all in with, so you probably don't want to lay it down...

If one of the Midstacks goes all in, I would probably lay it down. They have a slighter better advantage and can be a little pickier with what they go AI with. That is said assuming that none of the midstacks would be trying to steal the pot...Same if one of them calls or reraises a SS AI...however, if it's just a call, then you could call and see about checking it down (a little earlier to be doing this for monetary value though).

If nobdoy goes all-in or raises, you have a cheap (relatively) look at the flop and a well disguised hand if a 7 hits on the flop...Post flop play (if you limp) will be dependant on who else at the table plays along and whether you can push them around to steal the pot...

BTW, this would be a much easier hand to play from the button I also don't have a lot of tournament experience...so take my comments with that knowledge.

probably small raise.
its obvious you are owning this tournament, and everyone at the table, including the new guy is scared of you. so any sort of raise will most likely push all but one, maybe 2 callers out of the hand.

use your chip stack to your advantage. narrow the field.

OR fold. you can also start thinking about the final table already.
ride your huge chip stack like a surf board all the way to the final table, and only limp into the pot with Group 1 hands, everything else would be folded unless there is no raise when your BB. b/c lets face it, you've done most of the hard work already. your halfway to the final table, and your chip leader. let the SS's fight for position.

bet pot.