Basically the prototype will consist of bare min parts, but instead of a shield (which is nice) it still lacks what's really needed, so here's my solution..
A Ziff socket (just ordered one). A FTDI Basic breakout Arduino Board (Just ordered one) 1 20mhz crystal 2 27pf caps 1 USB female socket to connect and program your sketches.
a prototyping copper backed board to wire it all on I'm going to use 3 blocks of 8 pin dip sockets to fit the Atmega328p on (spread across) I'll program the atmega chip the IDE ISP sketch, but the chip can be lifted out and reprogrammed i think i'll add an ISP header to solve that issue.
once the binary is on the chip, we're good to go.
End User (out of the box) -
Step 1. Plug your USB cable into this device .... done Step 2. Pick up a Chip you wish to program with Arduino, place it into the ZIFF socket on this device, pull the leaver, so it sits in etc, done. Step 3. Run Arduino. Step 4. From the Menu, select "Tools" > "Programmer" > "Arduino AS ISP" Step 5. From the Menu, Select "Tools" > "Board" > "Your Device" be an Uno, or Lilypad or an Atmega. Step 6. Code a program for the chip you're programming. Step 7. Upload.
Step 8, lift out your CHIP, it's been programmed.... if you need to upgrade the ISP program on the atmega firmware, it will (once made) be acced via 6 pins for the ISP.
So it's not a Shield, it's a dedicated programmer, all you need is atmega chip and Arduino to get programming.... anything missing, need to be added, I expect shipping delays 3 -4 weeks this time of year so it's going to give me a lot of time to think up of the design..
But if it came in a kit or board, who would be interested in this kind of device?