I use to use an AdIDE 44 in my CDTV so I'd imagine it would work with an A500 and A570 with no problems. Simple install, it just goes between the 68000 socket and CPU plugs back in top of it. Then you can hook up a 2.5" laptop HD inside.
Then maybe you could through a Supra Turbo 28 on the side (it has a pass through), I use to have the A2000 version and that thing was awsome. It speed everything up when you flipped the switch to 28mhz mode. It was basically just a 28MHZ 68000 and it would speed lots of things up even games that you didn't want speed up. (there was a switch to through you back to 7mhz mode) Yeah that might have been my favorite accelerator ever. Then plug in to that a AlfaRam RA5-8M which also has a pass through, and then plug the A570 into that. Should be rock solid! ;-)