Regarding the TMS1270, only the PMOS version has 10 O outputs, which would all be addressed through the PLA anyway. I have no idea if that means more gates are available.

All CMOS devices in the TMS1000 family have the Vdd and Vss pins interchanged relative to their PMOS counterparts, probably because Vdd is supposed to be -15V for PMOS but +5V for CMOS.