Yes seems to be a bit of a rare beast, The flange where the cylinder mounts to teh frame is quite distinctive but I can't recall seing one like it before. The other thread has got a bit lost with comments about posting photos.
I wonder if it was a small power engine rather than a model, there were quite a few if you look back through old adverts in ME around the 1/8th HP size. teh head looks like it does not belong on there, would have expected a casting.
J