I have a 1.7Kw offgrid solar power setup, where I am its a remote mining town in lightning ridge Australia.
I run 4x icarus and a 5850 from my array.
Its not a cheap option, but it works, the array cost about 6-7K but I needed it for power in the first place, so now I just 'sell' my excess power through bitcoin mining.
You couldnt run a GPU farm economically but fpgas work fine. I get 1.5GH/sec @ 100w from the fpgas and 350MH/sec @ 100w from the GPU.
I also have wireless internet, so im not connected to any form of power or land line internet.
Wireless as in HSDPA or as in 802.11 ?
How is that working out for you ? Much downtime ?
Traffic limits / usage ? Packetloss ?