Be interesting the price, However in this day and age with tech, would be easy to make. I have 3 bandsaws (Small med & large) but currently you SCAN the part and a cad/cam machine can laser or water jet cut out these in a few minutes. Volume pays dividends, so in the past its always been my practice when paying a fab or metal supplier to make parts,, Might as well make 10 sets for the shelf, and another pile to sell to fund the endeavor.
** I can make my own, but would save me buckets of time & effort if I could find a set of plates to mount a Preunit Triumph motor and trans in a PU Swing arm BSA Frame, I would happily compensate or pay a reward for tracings or a scan of some.**
Here is some other plates from an old race shops collection, the former owner was a well known fab and builder of race frames, Flat track, TT and such. There are box sections for swing arms for various styles,
and mount plates as well. (Champion, Redline, Trackmaster etc etc)