I used to have a board - I think it originally belonged in a Packard-Bell PC- that plugged into an ISA slot and had 3 ISA slots on one side and 2 on the other. I tried it in my A2000's farthest ISA slot and it did work... gave me 2 extra slots, since it took one and I could use the three on one side.... of course, those cards were hanging in mid air, and the case wouldn't go on. ;-)
But it worked. ;-)
Many years ago, I had a 486 laptop for my university work. It had a black and white LCD display which led to not enough video memory when I hooked it up to an external monitor. It also had no way to attach a sound card. So I bought the expansion chassis which included two ISA slots. This allowed for an ISA video card and a sound card with a controller for a cdrom. But there weren't any slots left for the 16550 serial board I needed for my 14.4 modem. So I took the cover off the expansion chassis and plugged in the card you described. "Hanging out in the air" was standing upright for me, so it worked ok. I took power for the cdrom from another case with a dead 386 motherboard to appease the power supply. I turned the whole mess on with a power strip and it worked perfectly.
I've often thought about what the "maximum configuration" for something like an A2000 would be like. Plugging in a scsi controller for example would necessitate 7 drives. Then one could plug in a buddha board for IDE goodness. Then there's a deneb for USB, or the new rapid road thing. Could I hook up all of these devices using an existing A2000 case in spite of the lack of drive bays? Of course, such a machine would need a bridge board and an emplant board, CPU upgrade, 2mb chip ram/agnus upgrade, ethernet, sound, and whatever other goodness Jens cooks up. This led to the question about ISA expansion chassis. Because a 2000 doesn't have enough ISA slots for a video card, sound card, scsi card, ide card, and whatever other whacky things I could find, available IRQs aside.
Am I really the only retro computer fan out there that wondered what a PC that had a drive attached to every letter of the alphabet would look like? lol
brian