Having worked mostly for small companies I have never done this personally in a real world environment, but this seems almost like a textbook case for a normalized SQL database. The database diagram is easy to set up and then depending on what development resources you do have available (I know you said its limited) you can make either a web based front end with fairly quickly with a competent developer or else an Access or similar based front end can be made by just about anyone that is computer literate.
If you go with the Access type interface of course it comes with some limitations, but it is more robust than many people give it credit for. It can serve as a quick prototype unit management comes around and assigns a good developer to write either a web based or custom desktop front end.
