Web-based inventory & rental management system?

My wife coordinates weddings etc.. and we've amassed a substantial amount of equipment and decor that we're hoping to turn into a simple side revenue stream. I've been looking at inventory or rental management software, and most appears to be Point-of-sale focused. I'm looking for something (ideally) open- or shared-source and web-based for convenience and customization.

So far I've turned up Tracmor (www.tracmor.com) and Rentventory (http://www.rentventory.com/), and the bright idea that I just need to build something myself. A combination of those two would be what I'm looking for.

Any recommendations on something built or in progress? Or should I convince her that this is a worthwhile evenings & weekends project for me? :)