Not wishing to spoil the fun, but here in UK and Europe there are literally HUNDREDS if not thousand of what you would call scratch-builders of live-steam models in ALL scales.
Sure, if you are rich you can pay the likes of Station Road Steam or RMS to build you a ride on/in/or behind live steamer, but 99% of everything else you see in the larger scales is built by people like you and me, using lathes, mills, sometimes CAD and so on. Go to Train Mountain in Oregon on a steaming day and I bet you’ll not see a single ‘store-bought’ loco there - there are none that make and sell a Challenger or a Big Boy, although there are plenty of diesel builders.
In Gauge 1, f it ain’t Aster [they make kits remember] then its down to getting plans and a few castings from one of the many suppliers of raw materials and getting on with it. Look up Barratt Engineering, Keith Cousins and others of their ilk.
tac
Ottawa Valley GRS