Oh man that sounds sweet. So something like water near magma/fire/furnace/other "heat generator" boils and trys to force itself elsewhere, through pipes if necessary, pipes can be attached to pistons/valves/turbines,
All correct. Pipes will heat up and slowly start to glow red if the transported water and/or steam is too hot, and if the combination of pressure, temperature and pipe decay is too large, they will explode and leave behind a twisted, broken pipe section slowly rusting away. Pipe decay speed is dependent on the pipe material (copper, bronze, iron, steel and anything else I'll add) and will make the pipe look rusty. There will be both hydraulic and pneumatic pistons. The valve system is complex, but easily understandable.
turbines work like Thaumcraft Thaumic generators to power machinery?
Nope. You'll transform the energy from the turbines and pistons to mechanical power, and transmit it over gears, axles and belts to any kind of machinery you wish to power. Naturally, the native machines won't work like IC2 machines or stuff, and they won't just do stuff magically if you put stuff into them and give them power. For example, if you wish to operate a steam hammer, you will first have to build a working setup manually out of smaller parts, and then find a way to make the steam hammer move correctly using the gears you have access to. There will be transformer setups to and from BC/IC/RP energy, but the energy levels generated by this mod are insanely high, so I might add in a significant amount of conversion loss.
Or something even more awesome? This sounds exactly like my kind of mod.
All constructions will have to be fixed to structural support beams, larger mechanical elements will have to be cast in molds and moved by cranes, there will be sheet metal production lines, gigantic furnaces, and lots of other awesome stuff which I've yet to come up with. My ultimate goal would be to get all the stuff moving like the Zeppelin mod, but without the magic: Steampunk trains and steamboats.