Well, after messing up the hand, I may as well just say what happened.
You have 11 trivial tricks no matter what you do, given you can ruff the 4th heart (perhaps mikeh miscounted his tricks since none of the diamond ruffs are necessary to reach 11). The only question is whether you can do anything about your club and heart loser.
The only option I could see was the remote chance of being able to drop KQx of diamonds. Given plenty of entries, I could afford to draw all three rounds of trumps, since you can then play
♦A, ruff a diamond, cross to the last trump, ruff another diamond, and still have the
♥A to cross with if the
♦J is now cashing.
They didn't drop, so I took 11 tricks.
I missed the crucial part of the hand, which is also the crucial part that had a typo in the original post
If West has
♣KQ - likely given the bidding - you're actually cold for 12 tricks. You can only afford to play one round of trumps; by ruffing all three diamonds immediately after that, you reverse dummy - this in itself doesn't give you any extra tricks, but now when leading the last trump from dummy, West is squeezed, unable to hold onto both the clubs and the length in hearts.
(So mikeh's line in fact worked perfectly on the intended hand, even if somewhat unintentionally!)