I have not tried Unleashed yet but I'm sure any mod pack with the latest MineFactoryReloaded can use this. This is the setup I use in my FTB Ultimate 1.1.2 on a server. I have 3 wither skeleton drop farms. They all give bones and coal. I pipe the bones into my AE system then use an interface to extract it out (AE as buffer) with pneumatic tubes. Then to a fabricator, turning the bones into bonemeal, and to 5 or 6 bio reactors. Then I ender tank into the largest iron tank ever, and put those biofuel into full sized (36HP boilers with 9 iquid fueled fireboxes) and that setup is enough to power 6 full sized boilers with the addition of three biofuel generators. Mods required: Soul Shard Mod, MineFactoryReloaded, (Optional Railcraft or XYCraft for large scale liquid storage, Railcraft for boilers. Of course combustion engines from BuildCraft is still Ok, but much larger risk that they can explode than a boiler but boilers are the most efficient in terms of fuel usage and steam production,and Applied Energistics for awesome storage)
The best way to turn steam into EU is through an energy bridge, with the steam consumer touching the boilers and four additional liquiducts around the consumer, energy bridge in front, and it outputs about 380eu/t, consuming about 190 steam/t. That's only an approximation since steam to eu is about 1:2. Just like MJ. If you don't have the energy bridge mod industrial steam engines are the second best, as far as I know. But boilers -> energy bridge is the best way. One full sized HP boiler can produce enough steam for 2 energy bridge setups. So one boiler can make 720eu/t max, out of very little fuel once you get going with the heat. But be careful, make sure you have an aqerous accumulator supplying a constant water source (Both source and flowing water around 3 sides of the accumulator is enough to have it running at max speed or the boiler can use up all your water and explode once it reaches the max heat; LP boilers 500 degrees, HP boilers 1000 degrees. Size of the boilers do not change the max heat, but larger boilers require longer time and more fuel to heat up. But produces more steam that you can ever imagine.)