Mike, I think my castings may have originated from Blackgates though I got them from Adrian via Italy at a very good price so hard to say no. Not sure how many of teh castings I will use as Haining's designs are probably best described as "stand off" scale (with squint and guide dog in some cases)
I think traction engine is a broard description which you can then divide up in to Agricultural, Road Loco, Tractor, Ploughing, Stump puller, Roller, etc.
If I do make another engine I may not go for the Superba as I have a soft spot for the class "TE" farmers engine which is a bit of a hybrid of agricultural engine and ploughing engine, could even do it at 3" scale which would only be a couple of inches longer than a 2" Superba. I know Alan at MJ Eng would like me to make a pattern for a 3" compound block as he only does one for the 2" . It would also allow me to make a vine plough rather than those common balance ploughs
Have you seen my A7 ?