I'd build an obsidian generator (thanks, TE) paired with a minium stone that converts it to logs at the speed of hilarious. Could then shovel it into a steam boiler, generator, or some other form of bio-generation...
EDIT: If you didn't want to be boring about the obsidian generation bit, you could automate that one glitch for turning redstone into obsidian. That would be kind of interesting and switch the input cost of lava for redstone.