Thanks I am familiar with the IndivisionECS. I may end up getting it for my Amiga 600. However there are several issues with that approach. First the A520 works with all my Amigas, so its very easy to use different ones. Also my Amiga 500 has the IDE mod so it can use a hard drive, and I find that changes it enough that it is not compatible with most hardware add-ons. Both Gortek floppy emulator and ACA 500 won't work on it, so I am worried that the IndivisionECS simply won't work.
What sort of IDE mod do you have? AFAIK ACA 500 compatibility issues are down to the specific revision of motherboard, lots of people have problems with them.
+1 for IndivisionECS, I have them in both my systems and they're among the most reliable bits of hardware I own. And you can see from my sig that I'm using them with two very expanded systems, so compatibility between the IndivisionECS and other hardware shouldn't be an issue...