Ok so I made it, I set up the Mingw environment and compiled MESS on a 64 bit Windows 7 using the buildtools package and the instructions found on the
Tools page. It worked after a few quirks:
[MINGW64] C:\Users\jolar\work\mame>git checkout didact_r4
fatal: unable to join threaded lstat
I fixed by an additional git config thingie:
git config --replace-all core.preloadIndex false
I also had to set my HOME environment variable before anything worked
Also the instructions lists two git commands on the same line which will not work.
However, this is soo much easier than my previous two failed attempts to get a Windows environment for MESS/MAME up and running. Thanks a lot for that!:)