Although I own a couple of the asp programmers... I built the Adafruit ISP programmer and I did 2 mods.. the first was to rewire the zif socket for the 43 - 2313 and 85 chips and the second was to wire the ISP connector to the SPI pins except the reset which must go to pin 10 for the reset to be under control of the Adfruit ISP sketch. I also use the AT - PA programming board which has both 6 and 10 pin programmer connections. This way using a dedicated Uno I can program virtually any Atmel chip that is supported by the IDE. I've not used it with a Mega 1284 or 2560 though. The AT - PA also has provisions for a 328 and a crystal or a resonator...
It has worked very well for me for over 6 month's... for the rest I bought a MK II programmer.
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I own a Digix and see no reason to even attempt using it as a programmer... Uno's are cheap enough that this method made more sense to me... Point of fact.. I used my genuine r3 for the dedicated programmer...