Thanks, Paul. Glad you liked it 🙂
I think Musicloops.com have a good setup for customizable multi-version uploading setup. I usually upload the full track, alt versions, underscore, loops and 15,30,60 cuts there as separate files, and then, in the submitting process, I define each one – name, verison and price.
The customer then has the option to buy only a certain version or loop. I also setup up a different price for the whole package that includes all of the versions. In many cases, people only buy a small loop from the package or a shorter version.