Bus extenders for the A500 are pretty rare (other than the standard harddrive sidecars). You could make yourself a simple single zorro slot with some isa connectors, some cable, a saw, crazy glue, and some short ribbon cable. This approximates the same thing as you'd find in a Dataflyer500 (i.e. female 86-pin to female 100-pin adaptor). Such a setup may not work with all cards without further modification (e.g. the reset function for A2091 cards would have to be hardwired). If you need to make an 86-pin male connector for a passthrough, try sawing off the bottom gold connector of an isa card with all of the gold contacts in place, cut it to be 86 pin, glue the two pieces together and solder each of the ribbon cable wires to the corresponding gold pin. This works great albeit a bit fragile and keep the ribbon cable short if you can.