I think it would be too complicated - having multiple different methods of registering items would confuse people. Some already have difficulty understanding that you put a price for the entire stack even though it warns you on the register page. I don't know if it's a language barrier thing or people just don't read this stuff.

I will take a look at it and see if I can think of a way to do it but auction systems don't really work with buying individual parts of a stack of items and having multiple methods would be messy and confusing. Really not sure how it could be done.