http://www.amazon.co.uk/gp/product/B0018...UTF8&psc=1
This is the Hario Coffee Mill Ceramic Slim Grinder.
Yes it's for coffee, but I'm assuming you could easily use it for flour. The great thing is, you can change the size of the grind.
I hold to the quality of this item 100%. I'm a through and through coffee snob having spent around £600ish on coffee making items, this grinder is stunning. Having said that, it will probably take a long time to grind much stuff, as it does take a lot of winding for a single coffee (but fresh ground is definitely well worth it).
If you attached it to a bike or something, to rig up the blades to spin faster, you'll be a very happy person.
Would it not be easier to go medieval and just get a massive weight to crush everything up, then just mechanise it?
http://www.dhgate.com/product/dhgate/150...tAodbjoAOw
It's not cheap, but apparently is brilliant for spaghetti flour.