If you're really professional about it and put a team together, it would work just fine, as long as you promoted correctly. Win100% 'loids are getting pretty sought after.
Legally, you can't resell someone else's released bank, nor can you sell disks that come with the UTAU program on it, I believe.
Practically, your team would have to be pretty bloody pro to actually get anyone to buy. You need a unique, usable, HQ voice, it better have a good oto, an appealing design both in design sense and in style, probably a website for it and an installer would be nice...
So.