Harris is underrated, and until recently Warner was overrated in T20s. About a year ago you could say that Harris was a better T20 batsman. Certainly, Warner wasn't delivering on his potential enough. But his game has gone to another level, he actually builds innings (in all forms). It used to be that he'd get into his 20s or 30s and then find a way to get himself out, but he plays smarter now, and three unbeaten domestic T20 centuries in a row is testament to that.
Over their careers, Harris>Warner, but Warner is definitely the better batsman now.
Shane Watson picks himself at 2.
Shaun Marsh at 3 also picks himself.
Wade can slot in at 4.
Mike Hussey should be at 5.
Dussey is an overrated T20 batsman but a very underrated T20 bowler, can slot in at 6.
Mitch Marsh is a great lower-order hitter. He can slot in at 7.
Steve Smith is an incredibly underrated T20 bowler. He's more or less useless with the bat coming in lower than 4, but he's a brilliant wicket-taker in T20s. His natural inconsistency works to his advantage, and he will work really well opposite the more stingy Dussey. He should bat at either 4 or 8, and he's probably not going to be able to get a spot in the top 4, so 8 it is.
James Pattinson deserves a spot.
Jason Krezja is another underrated T20 spinner, definitely deserves a run.
Pat Cummins is in the best attack, but might be kept from the team due to injury/preservation.
So that comes out as:
1. Warner
2. Watson
3. S.Marsh
4. Wade
5. M.Hussey
6. D.Hussey
7. M.Marsh
8. Smith
9. Pattinson
10. Krejza
11. Cummins
Three spin options (vital in T20) in Dussey, Smith and Krejza. Four pace options in Pattinson, Cummins, Marsh and Watson. Batting down to 8. Four of the best T20 batsmen in the world in the top 5 (Warner, Watson, Marsh and Hussey). Some power in Dussey and M.Marsh at 6 and 7, while Smith can squeeze out a dodgy 20 or so at the end of the innings if required. Pattinson, Krejza and Cummins can all swing a bat too.