Hey--its an excellent idea and deserves all the kudos its receives. Electrotrains 'Ultimate Cart' is another game-changer and I was similarly happy to see it released. Just ATX support will be extremely valuable--the ability to use these images through an SIO2PC-USB (or just plain SIO2PC!) adds another degree of importance and relevance to the software preservation project.
The original hardware, especially peripherals is slowly getting more and more scarce on eBay or wherever. That which exists is succumbing to the passage of time. Projects like your modifications and enhancements to Respeqt are essential to ensure we have valid alternatives to these very frail devices.
I understand your concern about the drives but these devices are very good because they still work quite well 35 years later and I guess they will still work in a decade or two.
Try to use your PC (or now your tablet) in 35 years... This idea makes me laugh !
These drive are like living objets. I mean, If you use them, clean them, etc, they can be alive for many decades.
If you put them in your attic and get them back 20 years later, then there is a risk that they died meanwhile.
So even when using SIO2PC-USB or any "virtual" devices, my advice is to still used the old devices at least a little bit.
I won't say that drives are like plants and that you should talk to them but we must take care of them.