okay, regarding exploits, I'd say, an exploit is a way to generate something out of itself.
like a setup currently available in ultimate: set up a 36-boiler (LP or HP), a bunch of steam engines, a couple of oil fabricators and some refineries.
and then watch the system generating steam, which generates BC energy, which generates oil and fuel.
and that at a rate of 1,39. meaning, for every consumed bucket of fuel, it generates 0,39 buckets of fuel extra.
or the classical energy out of thin air setup with magma crucibles, igneous extruders and so on, which was nerfed because it just was necessary to do so.
or another system, that might be interesting in ultimate: a minefactory reloaded farm, which also generates "sludge". the plants are quite nice (standard way of processing) but the really interesting part is the sludge. the sludge boiler turns it into sand, dirt, clay, soulsand, cracked sand and quicksand.
so the sand is irrelevant, but the dirt can be turned into plantballs and clay.
the clay can be turned into aluminium, silicon, lithium (liquid boiler fuel) and sodium (semifluid generator)
soulsand gives oil, coaldust, saltpeter (usable for fertilizer) and sand
cracked sand also fills an IC2 fuelcan, gives sand and a ton of saltpeter.
the oil cell (from the soulsand) can either be turned into fuel by a buildcraft refinery or by a gregtech distillation tower. the GT-machine gives sulfuric acit and nitroglyceryl, which can be further processed to nitro coal fuel. electrolyzing the sulfuric acid cells gives sulfur and hydrogen, and the sulfur can be processed with the sodium to the sodium persulfate cell, a very useful component for the grinder...
the system would be even more insane, if greg hadn't changed a centrifuge recipe, that allowed turning coal dust into thorium.
so, the silly thing is now: this setup allows growing a bunch of metals (like aluminium) out of plants. and it generates it's own fertilizer, and as a bonus, it also generates oil (real one, not biofuel).