Trapper,
How long does the 1/2" shaft need to be? Do you need the 2MT arbor to be drawbar or tang type? Would it hurt if the 1/2" shaft began about an inch+ from the spindle nose?
The simplest solution would be to buy a milling cutter holder for 1/2" shank. I don't have one handy to look at but I'd guess that the 1/2" dia would begin about an inch to an inch and a half from the spindle. If that won't work, you could buy a drill chuck arbor with the largest Jacobs Taper and grind the JT to 1/2" with a toolpost grinder. But at a guess, you'd only get about 3/4" of 1/2" shaft.
On your shipping problem from the US, I think a lot of major US companies have gotten gun shy about shipping out of the country. Plus a lot of companies and individuals don't like the extra hassel of the paperwork on even simple shipments and the moderately poor reliability of especially First Class Mail International. FedEx, UPS, et al, are so expensive no small buyer is likely to pay the shipping. That being said, my wife and I ship packages foreign regularly, mostly eBay sales. Loss rate is around 2% or less. Off and on I buy vintage radio parts here mostly for hams and re-ship them foreign at a moderate markup. I shouldn't want to get too high a profile at it, though. Because of the current political climate here.
Robert D.