how about something for educational purposes:
A Variation of the AVR-MT-128, but only single-sided (mountability) and with a SOCKETED processor, if it reaches its end of life, due to excessive amount of reprogramming it. The Processor can range from 16 - 128 (for JTAG). Even the 10K (Flash) / 100K (EEPROM) read/write cycles (e.g. mega16 / mega128) can be done relatively fast, especially in an educational context, where beginners have to use the board
Oh, another thing i almost forgot: Every Pin of the Processor should be available for external connection, not only the unused (maybe with jumpers to choose onboard/external use, like on http://www.unesols.com/products_pages/A ... atures.htm
The last thing on the wishlist for that board is: some 7-segment option.
Another board: Just some 7-segments and a RS232 connector (and a preprogrammed processor to control the 7-segments based on the data it gets via the RS232), so another board can use its connector-pins freely, with only the the RS232 pins needed to control xy 7-segment-displays.