With regards the ZX Spectrum ROM, from what I can remember, AMSTRAD made this freely distributable.
As long as you are not profiting from the ROM then you should be fine as you would ONLY be charging
people for the board, your design and construction time and then supplying the ROM free on top.
Hopefully you will get some more of these made because, I agree with Zozo, they do look good without a
case and I would be interested..
Russ