Can you do quality CAD drawings? If so, maybe the66mustang could make these for you for a good price as he has a CNC machine. you'd have to pay shipping from Holland, but aluminum is light.
Also, I'm sure there are manufacturers like March or someone else that already make suitable water pump and alternator pulleys. If so you could buy a set and would only have to prototype the crank pulley as you could basically clone the others. Might save some time and effort on the R&D front.