[Zope] does anyone know of something like this

I develop for a library and wanted to know if there was a zope product that might accomplish what we're looking for before we build it ourselves. We have a number of book club sets that are loaned out to patrons for a 6 week period. The way in which this differs from our regular collection is that patrons can reserve a set by date rather than just joining a waiting list. Right now the way it works is almost beyond belief in it's complexity and archaic-ness. As I say, we can build an application that will handle this but it seems like it might be a common enough situation that if there was already something out there that we could just modify we might be better off doing that. Kate