RE: New Fox engines?
It seems to me that producing a new Fox engine would be cost prohibitive. They would have to sell many thousands of them just to pay off the design and tooling costs.
I suspect they are able to sell their existing engines for the low prices they do only because they have crates full of castings and other parts from years ago.
If Fox would produce a 4-stroke (just about any size) at a price competitive with Saito and OS I would be in line to buy one. But with many modelers moving to gasoline, now is probably not the time to invest in the production of another glow engine.