If you just want to grab the data to put into a more useful format, as opposed to really needing to actually use them as drives on your modern Mac, you may be able to do it if you happen to have access to something that has a couple dozen GPIOs, works with 5V logic, and is running faster than 1 GHz.

An RPi would be perfect except they use 3.3V logic. There are ways to deal with that such as bidirectional level shifters, such as [1].

Anyway, if you can find such a system bit banging SCSI on the GPIOs should work. Heck, on the original Mac Plus SCSI it was partly bit banged and that was on an 8 MHz 68000 where each instruction took at least 4 clock cycles.

They used an NCR 53C80 SCSI chip which pretty much simply provided registers to read and write the SCSI signals, plus a little bit of logic to handle those few places where something too fast for bit banging was needed.

Looking at my copy of the SCSI 2 spec briefly, it looks like the only thing you might have to worry about is the spec requires at most 10 ns difference in propagation delay between any two signals between the two ends. If you needed to change multiple signals together and used some higher level interface that did them one by one that might be slow enough it would look like propagation delay to the other end.

That could be addressed by directly writing to the registers that control the GPIOs. On most system each register controls multiple GPIOs and you can change them simultaneously. With SCSI we'd be using enough GPIOs that we might have to write to 2 or 3 GPIO control registers, but that would probably be fine.

It looks like the next shortest maximum allowed time is 400 ns. Way too short for an 8 MHz 68000, but trivial for a Pi or similar.

[1] https://www.adafruit.com/product/395 or https://www.sparkfun.com/sparkfun-level-shifter-8-channel-tx...