The much easier (although somewhat less reliable) method of getting Plus ROMs would be to find someone on the list with a chip programmer and the time to make copies into pin-compatible EEPROM or Flash chips. The Plus ROM dump from CopyROM will work as source, as long as one's programmer's software has the ability to interleave programming content across multiple chips, one at a time. IOW, program every other byte to this chip. Program every other byte starting with the second byte to this chip.

Only less reliable because one must depend on someone else to program the chips.

I don't have the time right now or I'd volunteer. I hope to eventually do something similar for IIfx and IIsi ROMs for the SE/30.

Ouch. Digikey's price on the proper EEPROM is $17 each and $8 - $11 for the Flash. Yow. At those prices, it's almost cheaper to build a circuit board to adapt a PLCC (little 7 x 9 x 7 x 9 SM chip) version to DIP.