I was looking forward to the railway equivalent of a unicycle ^__^.(0-2-0 or A).
There was a diecast range very many years ago called 000 which was roughly the same size as N gauge. - but I suspect that is collectors prices. I had some but they have disappeared over the las t fifty odd years.
https://en.wikipedia.org/wiki/N_scale#OOO_modelsBe aware that Graham Farish is now a brand owned by the Chinese company Kader (same as Bachmann )and is one of the two main N gauge manufacturers and they are not cheap. You might find some older original GF stuff second hand.
What you need to cultivate is contacts in the field of 4mm to 7mm* scale narrow gauge modelling. They use N gauge mechanisms for their motive power and might well have some now unused bodies - you will need to provide a replacement chassis.
* - model railways use a perfectly sensible scaling system which maps 19th Century units of measurement to the modern world, so HO is 3.5mm to the foot, OO is 4mm to the foot (00 gauge still runs of H0 track - hence gauge not scale) and 0 Gauge is 7mm to the foot.