Airplane nuts the world over can somhow figure out a way to cooperate.
To date, Joe has several Allisons running the Russia and more on the table.
One of the issues is finding parts for Mikulins and Klimovs, and the know-how to make old piston engines run. There haven't been a lot of Soviet or Russian big piston fighters flying in the last 40 - 50 years.
When they did get some running, they didn't run long. It was more a result of the condition of the parts and bearings than anything else. Several people around the world, Joe Yancey included, had the foresight to scrounge around and acquire old aircraft engines from the period. These are the guys with the parts.
Apparently there was nobody in the Soviet Union / Russia who had the wherewithall to acquire planes, engines, props, and spares from the governemnt and save then for use by later generations of pilots. Seeing as how the equipment was government owned, I can see why that might have been difficult at best.
So the supply of spare WWII Soviet-era parts is quite limited and is mostly in museums one display unit at a time. A display Mikulin that hasn't run or had oil in it for 60 years isn't a great source of spare parts. The total museum engines hardly consititute a supply sufficient to restore and run some population of aircraft privately.
So they are stuck, design, tool up and build engines and propellers or acquire engines and props that can be made to fit and work ... and run well.
Paul Allen has an Ilyushin IL-2 with an Allison in it. The Russians and the world have a few Yaks of verious dash numbers with Allisons in them and now they have a MiG-3 with an Allison in it.
I suspect there will be a few more MiG-3's and Il-2/10's in the future, assuming a desire to fly these for the population. I wouldn't be surprised to see an AR-2, Tu-2, Pe-2 or other Soviet WWII plane fly at some time, either.
It probably depends on the desire to get something flying for display to the public or as private planes more than anything else. But they need to do it while the expertise to overhaul these engines still exists and is young enough to be willing to do it. None of the engine experts are getting any younger, and many are not passing the skills down to anybody.