There's a board on ebay -- the Byvac BV511 -- that looks ideal except that it's got sharp corners, costs about three times as much as I want to pay for it, and seems to have nobody else actually using it (which means no help from a community).
?? -13 6
PORTB 5 portpin: led
took me forever to realise that most of the basic essential functionality isn't even uploaded to the atmega by default - it's up to me to pick and choose which bits I want to fill the ram with and manually put it there!