I don’t think there is a way to do this yet, but don’t you think it would be more practice to chose where to put items (into backpacks or pockets) ?
I mean, it’s more simple to drop a single backpack with all the stuff in, kick zombie’s ass and pick it up after.
EDIT:
Just saw this thread:
http://smf.cataclysmdda.com/index.php?topic=3971.0
Seems that the idea has already been proposed… !