Bruce, how about this one from Bengs:
This "Danni" looks maybe closer to a Cretors
bore is 15 mm and stroke 18 mm
dia of the flywheel 80 mm - but you can also
make a solid one with 40 mm.
the set is milled all other materials raw.
website:
Das Modell der liegenden Dampfmaschine „Danni“ besteht aus einem stabilen Rahmen, an dem der doppelt wirkende Dampfzylinder angeschlossen ist.
Arnold