Not necessarily early game, more like mid game really, but I found a cute little power system...
MFR Steam Boiler with an Aqueous Accumulator with at least three water source blocks adjacent underneath it feeding it water. Feed steam into a Steam Dynamo with Turbine Conversion, Auxiliary Transmission Coil, and Fuel Catalyzer. This will require a minimum of Signalum upgrade.
This produces 420 RF/t. However, it is inefficient for 'on demand' power because the boiler will continue to consume fuel even if there is nowhere for the power to go, and it will cool off if you stop it. Therefore, this is best for 'base-line' power generation when your needs exceed 420 RF/t and the ability to produce 'peak power production' in other ways that are more stutter-friendly.
Optimal layout seems to be two Aqueous Accumulators with four water source blocks around them feeding to one steam turbine providing steam to four steam dynamos set up in this manner for a total of 1680 RF/t baseline. You will likely want to have filters on the water pipes at the boiler to avoid backstuffing your water lines with steam.
The most expensive components are the Signalum upgrades. However, you can get 320 RF/t out of Hardened engines by simply converting them with the Turbine Conversion. This means you can have more generators on the steam line as they will consume less steam. This brings the system down to a level where you can manage it as soon as you poke your nose into the nether, as the boiler itself requires nether brick stairs.