Perhaps this has been mentioned before, but I didn't see it in a quick scan. You will find a wealth of information about upgrade possibilities at http://colourclassicfaq.com/

There is/was also a wonderful site by Stuart Bell. I now get a "404 Not Found" error, though. I hope that this is a temporary outage -- his site is full of valuable information (and great photos of successful mods).

And yes, long live Robby!