About a year ago (4/21/02) I posted a link to someone's site where they did a modeling database. The lady did it for her husband who was a member of IPMS Huntsville. Here is a link to the original thread:
Model Database. The program is based off of Miscrosoft Office Access, but can be used without having MS Access installed on your computer. The data entry is time consuming, but it would be no matter what program you used or developed.
FYI I saved the program several times to my hard drive and renamed them. I use one for just 1/35 armor, 1/72 scale aircraft, sci-fi, etc. It makes it easier to update and maintain. I also have one for just aftermarket accessories like tracks, PE, barrels, decals, conversion sets, etc. It does help to make sure I don't buy duplicate accessories for the same kit (like two different gun barrels for a tank).