I just made some fettuccine with my brand new shiny stainless steel Marcato pasta maker / roller. The have opposing gears, detend gap selection, 10" by 2.5" rollers, and is fully stainless. Perfect fpr a grain mill.
I can unreservedly state that these machines will work as a grain mill. I pulled mine apart to see how easy it is to modify (put some grip on the rollers) and it is absouletely doable.
All you need to fabricate is a bit of a hopper which you can easily attach to the top of the rollers and Bob is your uncle.
They are $70 on trademe (for some cheap knock offs) and this is all you need.
I regret paying as much as I di to get my mill in from the States. If you want a grain mill - or have been thinking about getting one... don't fuck around - and just get one of these. They are the shit.
And they make pasta too.