FWIW, EETools recently added the TBP28L22N to its list of supported ROMs after I sacrificed a few for another project I was working on. So, if you can find someone with a TopMax you should be good to go. I have some blanks if you have the image. Feel free to PM me.
To be honest i just got a Disk II interface card recently for cheap, but all chips were missing, including the two Proms, so wondering if populating the card will be a good deal or a lost cause...
eventually soon the proms that are used in those sockets will be all used up and noone will even have the old programmers to make them (new ones dont use them) so decide soon if you want to fix it.. eventually those will be a lost cause.