I was going to put OS96 on some EPROM's so that I could do some bits for Solder, when he suggested that I get a larger ROM and use a switch to toggle back and forth. After thinking about it for a little, I decided to go one step further and put in a single 128K FLASH ROM. This needs a larger socket, a NOR gate and a switch, but will allow me to update the ROM with a little more ease than EPROM's.
I guess I could allow the Plus/4 itself to reprogram it, but I think that might be taking it too far as no one else but me will be using it, and I have a lovely EPROM/FLASHROM programmer. It will mean I could have 4 different ROM's on here if I wanted though - although only 2 are needed just now....but you never know!