This is my take on a breadboard breakout ("breadout?") for the prop 2.
It includes flash, temp compensated xtal oscillator, LDO regulators. It may even include a FT232R before the weekend is out, and if it fits.
It can be used stand alone, or castellated along the "C" for cut lines, and soldered to the back of a full size breadboard, to provide clean breadboard playground where any node can have signal injected (sine, current source, dac, etc) or measured (adc). This will lead to lots of fun.
Along one side I have added intermediate nodes for construction of external R2R dacs, audio filters, led resistors etc. Along the other side servos or sensors can be connected with the usual 3 pin headers.
I think it would be fun to hook up a projector aimed at the front of the breadboard and have the Prop2 itself project Fritzing style circuits, overlaid with live node status (voltages,timing info, waveforms etc) in real time, adjacent to the nodes. I'm also looking at an aligned LCD to do the same without projection hassle.
Thanks to jmg for the parts suggestions.