well, they're supposedly dumbed down versions of VL-1/PT-1 heritage.
http://weltenschule.de/TableHooters/Casio_VL-1_PT-1.htmli've got one opened up around here but haven't gotten round to finishing it.. it's residing in a shoe box somewhere.
so: no ADSR synthesizer.
no 100-note sequencer memory either. you would need the calculator chip for that one, i suppose.. who knows.
(extreme) pitch bend pot is definitely possible, since it isn't crystal clocked.
iirc there's separate outputs for melody and drums, so that might be of interest. i managed to bring out the extra guitar sound and in my notes i wrote something about a squelchy fuzz bend. that probably made sense to me at the time, but it's loooong ago.
all in all it's very basic, this ain't no SK-1 holy grail style keyboard if that's what you're after.
if it's just for laughs, then yeah, this might be your thing. not too much info on the 'net to be found though, apart from the Burnkit Frogsquasher.