How about as a "Falk 456? / Schoenner 107?" with added boiler diameter, flywheel diameter and overall dimensions in your listing.
I'm rather leaning towards the Schoenner manufacture, based solely on the firebox's slotted vents, as opposed to Falks more typical porthole vents at this smaller size overtype .... provided of course, that I'm judging the actual size of your engine correctly!?!?