If you are playing with Phoenix or an event is in play to allow characters to continue to fight after being KO'd.
Can you still hit a character that is already technically KO'd in order to beef up venture?
I say, yes! Beat that dead horse! :D
The more or equally interesting question is removing hits on the 'dead' character solely to affect venture total. ;D
We discussed the venture total thing at length here:
http://www.beenhereandthere.com/SMF/index.php?topic=97.0