> (other than regressing
> to an old version of MAME)
If you want, I made a fork off of what's in the MAME code repository as of tonight, so it should be roughly in sync, ROM-wise, with mainline 0.189. The major difference is that it will have any potentially shaky changes that people held back prior to the monthly release. So, no warranty, no support, if it breaks, all you get is to keep the pieces.
The Github page is here: https://github.com/MooglyGuy/oldtrax
If you just want binaries: