A high-end machine that you could build would be the processor. It would be made by combining a chest, a MFSU, a compressor, a macerator, an induction furnace, an extractor and a canning machine (possibly an advanced machine, advanced circuit etc). I don't know how easy this would be, but ideally it would be 3x3x3 blocks. The GUI would look like two chests sandwiching a furnace interface. The processor would take resources from the left/top checst and turn them into useful thing, for example ores into ingots, iron ingots in refined iron, coal into carbon plates or if there is flint into coal balls. It may be very hard to program, and may need some balancing, but I think it would be cool to come home from mining and basically dump my whole inventory into one chest and let it do all the work (as is sort of possible on a huge scale with BuildCraft).
