Unless someone is making and advertising them, I think that sort of thing is usually best locally made.
Maybe self made.
Shipping would be quite high.
Ask around your local shops and get quotes with the drawings.
I think you can likely build it yourself, except maybe the lathe work if you don't have one.
Id source all the stuff first, motor, gearbox seem to be the most important.
I'd buy the materials, cut to length from suppliers
Drill and bolt it together yourself.
Outsource welding and lathe work if you need to.
Have a look at the plans, I think you can simplify some things
For instance
Instead of rollers turned down to fit bronze bushings, can you just buy large pillow block bearings
to fit full sized round stock.
There is a mastersmith, maybe Josh Smith who has a beautiful rolling mill
a fabricator built for him, but it's huge $$$ and features
http://www.bladeforums.com/forums/showthread.php/869126-rolling-mill
Oh wait that's your thread too.