There's a utility called ClrMame which can rebuild new Romsets from existing ones to work on new Mame versions but if you don't have certain dumps it won't be able to build any Rom that needs it. Additional to that, it's a bit of a pain to use.
I got a set something like 7 years ago and have been happy to stick with it - I've only now found the need to start finding/building new Roms since I've got Android Mame versions that need different Romsets to what I've got.
Bottom line - the way the Mame project is run is a bit of a running joke. Being anal about how things are emulated and breaking stuff just for accuracy sake is one thing, but making people endure continual shuffling and renaming of the files that contain the actual Rom dumps is a total pain.