> I don't know much about fpgas or vhdl - but whats the smallest, most
> economical fpga to fit the spectrum ULA in? - I don't need the ROM,
> RAM or processor in there...

That depends on what you want to do.
The ULA itself is very small, it would probably fit in the smallest
FPGA you can find. But then you would need to use external RAM for
the video RAM.
To make it possible to use a single external RAM I used the internal
FPGA RAM for the video RAM, and if you also want to do that you need
an FPGA with at least 7k byte RAM, i.e. Spartan II 200k or bigger.

The current implementation cannot use external RAM, it must be
redesigned to be able to use external video RAM.

A few days ago I got an implementation of the sound generator in
spectrum 128 from the japanese team that is working on the MSX.
I haven't tested it yet but it should make it easy to also implement
a spectrum 128.
If you also want that and other additions you might soon fill up a
200k device anyway.

/Daniel