On30 too "whimsical"?
Well, there's an On30 group on Facebook--more than 1,000 members strong in just a short time--that regularly displays some of the finest narrow gauge (or any gauge) modeling you'll ever see. Some members are also participants on this forum.
Some folks prefer a whimsical look, and there's certainly absolutely nothing wrong with that approach. But those who aim for a more realistic/prototypical look with On30 are creating models and layouts that rival anything out there in any scale.