This is not what I originally intended to release, but as I figured that my vision is taking ages to materialize I'm releasing what I have. This is built from the latest core code that is capable of 32x and SMS (with lots of internal changes from last Wiz version), but I had to disable 32x/SMS support as they are not really usable (hence the 'beta' tag). So current known issues are:
no 32x/sms yet
no smooth scrolling in pal/50hz mode (still need add this to kernel/firmware)
forced vsync because of double buffering, so no way to disable frame limiter (again need to patch kernel)
occasional sound glitches (also firmware problem)
no use of hardware scaler yet (needs work)
That aside, Genesis/MegaDrive support should be solid, also Sega/Mega CD (needs BIOS in <sd card>/pandora/appdata/PicoDrive/ directory).
Enjoy!
EDIT: updated to beta2 which is beta1 with fixed readme.