Are there combo gates XOR followed by AND? (4-bit identity comparator)
No, it seems pretty definitive that while there are 4-bit identity comparator ICs (eg. the 54LS85 and the 74LS85 you mention) the lowest pin count packages they come in is 16, giving you a few unnecessary pins.

DIP-12's seem very rare in general. Even the PIC microcontrollers only come in DIP-8 or DIP-14, and CPLDs/FPGAs don't seem to be available in packages that small. If saving the 4 pins is that important, the only other thing I would suggest is to design your own - you could use small SMD discrete logic ICs and build them into a DIP-12 sized custom PCB.