I was able to get a new Sun/Toshiba SCSI DVD-ROM for $25 shipped. Not bad.

Here is where I got it if anyone is interested, they have 1 left (I gain nothing by linking to this auction):

http://www.ebay.com/itm/251229236002

I think the InTech CD/DVD SpeedTools driver will work for System 7, but I can't even test it because the demo doesn't work.

I contacted InTech to see if they can fix their demo.