There are no replacements for the 2732 EPROMs that use flash programming. There are some One-Time-Programmable 2732's out there, but probably not a lot. They were in plastic packages without the quartz window. Most of the 2732's available today seem to be used chips. I don't think any manufacturer makes them new anymore.
A physically larger chip can be used in place of the 32k chip, but you'd need to build an adapter because of the higher pin count.
Chips that have the 28 prefix, such as 2864, are electrically erasable, as I recall. But if you adapt one of these to the 24 pin socket, you'd need to disable a critical programming pin, so you're better off with a UV erasable chip anyway, since you would need to remove it from any socket or adapter.
Erasing the EPROMs however is not too difficult as long as the UV source is adequate. It usually takes maybe 10 minutes to completely erase a chip.
