Here's a project I just completed-- a model of a Rhaetian Railway Allegra set. All are powered, running on the 35.5mm chassis. They are really not 1:450, probably closer to 1:420 or so to fit the shells.
I made the control or "A" unit shells with 3D printing (Shapeways FUD), and bashed the "B" or middle unit from an "A". For the B unit, some build-up of the shell was done with a mixture of squadon putty and thick ACC glue--this mix hardens nicely but has body, and sticks well to the acrylic shells. It was sanded to contour. I painted the shells white in preparation for decalling, as the decoration is the "whole side" decal technique, and artwork was made on clear decal stock. The bodies were touched up with white, black, red, and gray paint where the decals didn't reach. The pantographs were made from bits from an etched brass ship detailing sheet. If anyone's interested in making their own, the lead units will be on Shapeways or feel free to contact me!
Jesse