Current plan is DC to AC to DC using off the shelf tech. That way any excess KWH is sold to power company. The grid becomes our "battery bank".

Am exploring a 600V to 48V Battery Bank system to power the miners.
So it would be 600V DC (solar array) to charge controllers (Morningstar MPPT 600's) to 48V Batteries (probably US Battery 425A/hr L16 HC's in strings of to 48V/12V DC/DC converters to the miners. System would include AC/DC battery charging for those non-sunny days. Backup genny for battery charging when/if the grid goes away (I own a continuous duty rated 35Kw Onan that is just looking for a purpose in life). This is a grid isolated system technically.
Downside of that route is conversion inefficiencies, cost of batteries, cost and complexity of DC/DC conversion(s). Upside is that the miners are effectively UPS'ed and battery backed up.

Am also looking at using Syn-Gas to power a genny. Which is wood gasification, purify and warehouse the gas (methane, CO, and minor amounts of H2 in suspension, Nat Gas effectively), then use the Syn-Gas to power the genny to do battery charges periodically. Logging scrap is plentiful here and currently considered an annoying waste product of the logging industry.

Am also investigating using wood gasification Syn-Gas as a feed stock to a Fisher-Troops processor to make liquid fuels (diesel/gasoline, GTL-Gas to Liquid). http://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process

Another possibility is using wood gasification Syn-Gas in Bloom Energy processors. Like the ones used by eBay, Google, and Walmart. http://en.wikipedia.org/wiki/Bloom_Energy_Server.

We have time to sort all this out and make an informed decision. As we move forward I'll try to remember to post pics.