Using BuildCraft, Forestry, Industrial Craft and Equivalent Exchange I was able to make a fully automatic diamond farm, with output around 2 1.2 diamonds per minute.

Todo: Make a pipe system that will automatically refill steam engines with charcoal (possibly RedPower 2’s transportaion tubes, since there doesn’t seem to be enough space for any more buildcraft pipes without them connecting to existing ones, Eventually connect charcoal distribution into existing production line of diamonds while adding filters)