Nah, wouldn't happen, not in the main continuity again at least, or at least I hope not. The last New Avengers crossover, now pretty much considered non-canon, same with Spider-Man's appearance in Marvel TF issue 3.
Hm, the last one got so-so reactions, so I wouldn't expect there's too much call for it. Revolutions also makes crossovers a bit odder. I could see an out-of-continuity one, but I wouldn't bet on it.
No. A TF/Guardians of the Galaxy crossover featuring a certain freelance peacekeeping agent, though YES
Forget the Guardians of the Galaxy, I'd just be thrilled if Marvel would license Death's Head to IDW since Marvel isn't doing much with him.