I have had this idea to make a very small development board for the Propeller for a while now. The idea is that you can have it on your keychain or something and just plug the entire unit into a USB port. The port powers the device and there are female headers that allow you to plug other things into it. I might add a ADC just to get some analog signal input.
So I give you /drumroll the Propeller Development Stick or PDS V1.0.