There seems to be an interest in GWR steam locomotives, when not looking at the many 'industrial' tank engines. How about a County 4-6-0? It would be nice to see a high-quality model of this.
I've previously mentioned an interest in:
ex LMS 8F 2-8-0. True, Hornby have re-introduced their quite reasonable model, but ....
ex LMS Jubilee - many variants. Bachmann's is nice, but old now, and the really interesting variants are of the even older tooling.
ex LMS Parallel Royal Scot. Bachmann's is old now. This would be a superb addition for the enthusiast.
OK, I'm an early member of the 'please bring out an Accurascale BR Class 40' - still waiting ... !!
Other diesels could be the West Country based hydraulics - 35 Hymek, 42/43 Warship and 52 Western. All 3 of these have a disproportionately large following. Accurascale variants could be pretty interesting!!
Al.