@Daemonblue: Actually, if you're playing with Forestry with TE, you can pulverize cobble into sand, craft the sand into Bog Earth, then stuff it into the Peat Bog - after all this, you'll have a net gain of dirt. (a LOT of dirt, if you run the Peat Bog for any significant amount of time.)
Also, I think you could play about with the Moistener - I believe Mycelium will also work quite well for methane, and I believe making Moisteners doesn't require redstone - you might just be able to get everything you need out of lava centrifugation, and get plenty of clay to boot. Also this will generate considerable amounts of mulch, which you can feed into Bog Earth production - something of a synergy there. Of course, the tricky bit is pumping stuff into and out of the Moisteners...
(Yes, I haven't found many diamonds yet. Is it obvious?
)