I think what would really sell (as I'm sure it's been mentioned several times already) and what I'd love to operate is a conventional / legacy / whatever 2-4-4-2 (or comparable) articulated little logging mallet like the one shown at the Northwest Railway Museum: https://www.trainmuseum.org/in.../steam-locomotive-11
US Plywood 11 is a 2-6-6-2. I would love to see a scale model of any of the Baldwin logging mallets. Mantua did well with their many versions in HO. However, the O scale market does not appear to be very interested in a small articulated. Sunset recently announced Rayonier/Sierra 38 and received a very modest response. I dont see Lionel or MTH investing over $100,000 in tooling for a logging engine in today's market.
But if anyone does, I'll take two.