MCU Motherboard

[Webbot]

Was wondering if anyone had ever tried producing a 'motherboard'?

What I'm thinking is: look at a Mega 8 and a Mega 32 - whats different? Well: they have some pins in common like ADCs, some of the I/O ports, RESET, +5v, Gnd, ISP pins etc. All that changes is the packaging (ie the Mega32 has more I/O pins and the Mega8 may combine some pins together into a common pin on a DIP package). So if you created a superset of the possible pins - lets say there's 64 of them. Then I would have a motherboard that contains all the common parts: ie power supply stuff, and all of those prickly header pins, and the ISP - but NO controller. instead I'd have a 64 pin connector.

Then you could create controller boards which just have the microcontroller and a 64 pin connector which is wired up to support the I/O pins etc that the particular controller supports. So then you could swap out an ATMega8 for an ATMega32 without having to create a whole new board.

I know this means that the overall board would be more complex and larger than necessary - but has anyone tried it? Does it make any kind of sense?