What would be required to develop ATtiny13 using the Arduino Diecimila? Adapting the IC is straightforward: a small "daughter board" to plug into the 28-pin socket on the Diecimila board and the ATtiny13 would plug into that. All that's required is power, ground, and the serial pins that allow downloading.
A bootloader, of course. Anyone up for the task?
What else is needed?