My list would be....
Openers:
Smith, Cook, Gambhir, Sehwag, Watson
Would depend on whether they'd make the Indian side, pretty much. I can't see Watson making India or England as an opener, but he'd still find a spot in a Kallis-esque role, and South Africa's other opener is a hack. Cook might not make the Indian side, but I still think he could - or should - do a better job than Gambhir - the only reason why Cook's stats seem meh is because England's less receptive to his technique - which could also hurt Gambhir. In fact, Gambhir might not make the English side, thinking about it.
Middle-order:
Amla, Tendulkar, Laxman, de Villiers, Kallis, Clarke, Hussey, Trott, Pietersen, Bell, Sangakarra, Jayawardene, Samaraweera, Younis, Ryder, Chanderpaul
Broadest definition, so I reckon all of them could make it into every side. Reckon Sri Lanka's actually the toughest to get into, as their 3-5 are all guns, and their 6 is an all-rounder who Sri Lanka might not be keen to give up.
Keepers:
This is hard to say. Dhoni I don't think is good enough for England or Australia, Haddin suffers from keeping, so India or England won't take him, and I don't see India replacing their captain for Prior. Reckon all 3 would make a squad however, as would Boucher.
Spinners:
Another tough one. You'd expect Swann or Bhajji to make every side, but I don't see their current sides giving one up for the other. Shakib might but it's debatable whether England or India would give up their spinners. Vettori's an outside bet but England or India did pick him, it wouldn't be for his bowling. Expect all of them to make a squad however.
Seamers:
Steyn, Morkel, Broad, Anderson, Tremlett, Zaheer, Amir, Asif, Roach
Would depend on whether they'd make England, as Uppercut said, as all other sides have either no 3rd seamer (most sides), their seamers are always injured (West Indies) or their seamers are all on an even level and none of them are great (Australia). Outside chance that they could leave out Amir or Asif on 'character grounds', but I'd think they'd still pick them if they were available. Considered Malinga, but he's often injured so I don't know if all that many sides would take that risk.