Sorry, I should have googled more first. The manuals are at: http://www.tech-tools.com/romtools.htm
I looked at the FlexROM III, it appears to emulate just flat 8 or 16 bit devices. PLCC's are more complicated, they frequently make use of an LPC interface that clocks in 4 bits of data at a time (as I recall) to get the address into the chip, then clocks out 4 bits of data at a time. I think an operation is 16 bits at a time. This is all transparent from the system's perspective. However behind the scenes it is a complicated dance.
LPC = Low Pin Count
-Dave