Hey Tom
Thanks for your contribution. This is actually a direction we are thinking about taking.
You can see a preview of that here Arduino Boards | Flickr
you can see the evolution of almost all the arduino boards including the last module which are the arduino stamp and its USB interface.
We experimented with this tiny smd module that has the same pinout as the Basic Stamp or BasicX 24. On one of the sides there is a standard pinout for RX TX GND and 5V that matches the USB module.
We also made a Bluetooth module with the same pinout and a small sensor module that matches the board on the other side.
I realise my explanation is a bit messy but it was just to give you a preview of stuff that will be available in the near future that goes in the direction you mention.
let's keep the discussion open:)
massimo