Got this last year via Aliexpress - they have been listed on EBay but tend to be a bit more expensive. Sizeable and solid piece, about 9 1/2 inches overall length and a 3 1/2 inch flywheel. Beautifully finished, had it out for a fun run today, it's strong enough to run a Mamod workshop at reasonable pace and on a solid surface rather than a wobbly turntable it doesn't move around at all:
Recommended if anyone's looking for a decent size hot air motor.
Dave