I agree with you on the handling of the longer frames.

I built a stainless Mini Vaquero Single Six into a 4" 5-shot 10mm

At 4" it handles great. 4" is a really handy barrel length for a single action, and you get away with not having to do gymnastics with the build to get relatively normal ejector rod function and base pin function for cylinder removal.

The 3-1/2" 480 required thinning the ejector rod actuator, thinning the base pin head, and the provision of a shift gate in the ejector rod housing to allow the base pin head to pass the ejector rod actuator.

Still, all function was retained, and the gun was very handy. It just takes time/money.