I don't think Kilmer is in any shape to do more than maybe a cameo after battling throat cancer.
This is from December...
It looks like he has been doing the convention circuit recently, so he must be healthy enough to travel and do that, but he definitely doesn't have the hot shot screen presence he once had.
These photos are from a couple of weeks ago in Detroit:
http://www.mlive.com/entertainment/i...his_custo.html