Thanks for the thought, but no; they (and their descendants) all require #WE and a bidirectional databus. The parts I think I'm recalling were specifically intended as a drop-in replacement for designs that did not support writes to ROM; everything was done by reading, using the address pins to...
Folks.
I have a distant memory of a family of JEDEC-pin-compatible memory devices (EEPROM or possibly NOR flash) that could be programmed in-system by address manipulation, i.e. without needing the system to explicitly support writing to the ROM.
No amount of searching has turned up anything...
A bit late to the party, but in case it's worth anything... I just picked up an HP 9000/382 with 20M/525M off eBay for $240 shipped. This is a 25MHz '040 that will run HP/UX up to 9.x as well as Linux or NetBSD (also HP Basic, or Pascal). These tend to go for a bit more, but if you're patient...