Never mind, I found a way to solve this (without ignoring those slot-options)... it's actually only the device description that I need to find out and can't because it's not in "standard" -listxml, but I *can* live without it. It would still be better to list *all* available devices in normal -listxml, though.
EDIT: SVN r6859 supports this cleanly now and reads the descriptions of the "new device machines" dynamically.
nice - thanks.
BTW: Thanks also for all your time and effort. In fact that goes for all who work on the MESS fork of MAME, QMC2 and MESSUI !
I personally use QMC2 with my custom compiled MESSUI in which I swap the colecovision bios for one that the annoying 5 sec delay can be bypassed by pressing fire button.