Bachmann just announced new 009 carriages, so there's at least a niche market for a big maker to continue in. IRM hired a narrow-gauge model designer from another firm.
My long-shot guess: a Tralee & Dingle Light Railway Hunslet 2-6-0, convertible from 009 to 00n3, in TDLR, Cavan & Leitrim, or West Clare Railway liveries. In business, you identify an unmet desire and create a new market.