@fzuern: exactly, you just need to run vcredist_x86.exe that comes with QMC2 -- glad you found it!
@ASH: yeah, they are two separated programs, both get installed, but you have to choose which one you want
. I can't say why the MESS variant didn't show up earlier, but the installer does work fine for me (and others, I suppose).
The software-list support is currently disabled (as mentioned earlier) due to the fact that current MAME and MESS both don't support "-listsoftware", the CLI command I currently use to scan and cache the software lists.
ATM it's unclear if the way to go will be to use -listsoftware or to scan the hash directory directly... but as I would like to stay with official CLI commands / options, I'd rather wait for a final answer (still pending).