1) How on earth are you getting enough blaze rods to have a surplus of power from them? What are you using to spawn them? (I'm assuming you are not using Ender IO...)
2) Is it actually possible to get a surplus of energy from a lava fabricator? It takes 200,000 RF for a single bucket... and I don't think you can get that much energy from a single bucket... or can you?!
I now have four blaze spawners on cursed earth being dealt with by MFR Grinders. I've been moving the spawners from the nether via diamond dolly. The cursed earth under the spawner allows it to spawn without a player in the required range, and blaze spawn regardless of light level. If stick on blaze rods drops below 500, an autospawner kicks on to help keep up.
Those rods are currently going into the boilers, which produces steam for a max sized BR turbine putting out a consistent 28kRF/t. I have only to power the grinders (which only draw power when they act) and the autospawner if needed. Everything else is gravy. And that's a lot of fricken gravy.
To be honest, I haven't run the numbers on the lava fabricator setup yet. I've put it together and let it run the turbine for a while, and it does net positive power. That said, I did just cut the supply of rods and introduced the buckets while the boilers were hot. If I had to guess, I would say thengains are due to the length of time a bucket fuels the boiler versus the amount of RF the turbine can kick out in the same span. I'm sure that once I have the numerical data in front of me, I can trim the fat and make it a mean, self-sustaining system. But really, it was more a.proof of concept build than anything else.
Backup power is generated on a separate network (powering just my ME and a new RFTools dimension) with gunpowder and mob essence (from a witch spawner farm) processed in a bank of Reactant Dynamos.
Edit: The one problem in have with the MFR Boilers is supplying water to them fast enough to keep up. Right now I have one Ender Tank (set to export) for every two boilers. It works, but its not visually appealing. Any good pipes to move an assload of water in a hurry?