If the SD connector had been mounted in a cut out of the PCB it could use the available slot.
It would require some rerouting, it might be possible - I'll probably try it...
I wonder if intensive LEDs would be visible through the plastic, it could be sanded down a little maybe... label could have indicator texts for the red and green lights...
Don't you drill the holes with the case closed, is it difficult?
If buttons are top mounted there's not much height for the buttons, something like 12-13mm.
I found some decent looking buttons, illuminated, but they're 25mm deep so they won't fit unless room is made on the PCB for a larger cut out.
I remember seeing a VIC-20 case in a blue 3D shape when I googled, don't know if it's a freely available drawing. I could whip one up, I've done a Fairchild Channel F cartridge and also Videobrain cart and some smaller stuff. I was considering a 3D print, I'm expecting it to be a lot more expensive than grabbing the cheapest decent looking cart though.
I guess I can do any changes I want to, PCB can be increased in size a little more, things can be moved around, flat cable for IEC going out through slot sounds neat and "sinking in" the SD connector so it can use the slot as well. Regarding the buttons it could be quite possible to use plain "keyboard push buttons" those little black clicking ones and either use the ones with a long button or if adding LEDs - use a transparent/semi-transparent piece of plastic as a button, hole doesn't need to be more than a few mm, point a LED to it and the LED and buttons are solved with the same hole - on top. Only two holes need to be drilled, push buttons from above. Even better - those micro switches in mouse buttons will fit, two of those, an up-side down mushroom shaped transparent piece of plastic through a small hole and the button is done.
The IEC cable could even have sockets, plain strip - in case you'd want it removable.
So, two of these on the PCB:
Semi-transparent button, perhaps something like this:
http://static.rcgroups.net/forums/attac ... 1153794044
Point leds on the plastic button and LEDs should be visible enough - just like they do on mouse scroll wheels with the transparent silicon rubber for that extra cool look.
I understand the decisions on how it was made from start, it needed to be cheap and fairly easy to make and readily available parts. Anything special makes it more expensive and harder to source parts.