A while back in BLADE, there was an article on this rolling mill  Hugh McDonald had constructed and drew out plans for his mill.  One year when I went to Batson's, I picked up a copy of the plans and started building the mill.  The plans are pretty well drawn, but be warned, they are a combination of metric and standard units.  The mill itself wasn't too difficult to build.  The most expensive part would be the two rollers and the cam at the bottom if you need to farm it out.  

When I started building it, I thought I'd be doing myself a favor by using a gear reducer instead of the different pulleys.  While it was easier to build, it also had a much lower output torque.  I've recent rebuilt it with the pulleys instead and it is considerably more powerful.  It's great for reducing stock evenly.  When making damascus, it also makes an incredibly straight pattern.  

In his notes, he says that he hopes that lefties will think to reverse the plans.  I think right handed people should.  I'm a lefty and I built it as the plans dictate.  My tongs stay in my right hand and the left hand is free to use the lever or grab the hammer on the way back to the anvil.  There is only one thing I would change were I to build another, I'd make it taller.  Evidently Hugh is shorter than I am!