Looking for a hack/advise - simple database

[Club3G]

I'd like to put up a registry on my forums. One of the vB licenses I own (I have five total) is for sevenstring.org, a guitar website. I'm looking for a simple app that will let my users "register" their guitars. I'd like to have just two fields, the guitar itself, and serial number, and let users determine how many total lines they need.

Eg, I own three guitars, so in a showing of the registry, you'd see:

Chris - Guitar #1 - Serial Number 123456789
Chris - Guitar #2 - Serial Number 123446789
Chris - Guitar #3 - Serial Number 123446789

I haven't seen anything in looking around that looks like it does this. I know I can add profile fields and probably display them that way, but if I do, it would be a fixed number, correct? I'd like a small dropdown (kind of like poll options) that users can select how many "lines" they need, and then be able to enter the info after a refresh to show the correct amount of selected options.

I already use vBGarage for my member photo gallery, so that isn't an option, and honestly is overkill for what I'm looking to do here anyhow.

Any advice/insight/suggestions or even a link to something you think might be workable/hackable into this would really be appreciated. Thanks!