I've spent most of today playing with some old zx spectrum stuff. I looked out my old 48k spectrum (I actually have 4 or 5 now!) and some interfaces I have for them. I hooked up my Interface 1 and microdrive, tried my DivIDE (which I couldnt get to work on a 48k for some reason - need to find the manual...), and a Disciple interface. I had to find a floppy controller but had an old Amiga drive so used that. New PC drives dont work because they are hardwired to the wrong device. Still, the disciple interface works pretty well (its a clone though, not an original). It loads really (REALLY) quickly, and theres loads of storage. However theres no through connector (on this one) and I can use the interface one's RS232.
I also tried using the interface 1 with other things plugged in, and it didn't work either - although plugging an interface 2 did work. I have an interface 2 card that takes an eprom so thats a possibility as well. We could (for development) use an interface 1 and interface 2 to try out ROMs.
The other thing we could do is supply new ROM's for the spectrum itself, but thats not what we really want to do....
The first downloading code has to be written on the speccy, but after that It should be easy enough to develop for. However, most of this is Russells problem, and I've just been having fun for the day.