Nick, Angel, everyone; I consider what I am about to show you to be, in no way, on a par with the work you guys are currently doing but still, I would like to share my current project.
Roden's Opel Blitz Radio Bus with scratch built generator trailer:
I guess this is more a straight kit (hobby manufacturer's conversion) than a home built conversion per se, but I have, of course, added additional underbody detail, interior and roof bracing, duck boards down the center aisle, a number of figures and more appointments overall.
All exterior doors and windows will be posed in the open position to better see the interior detail.

Note package tray added above side windows. (I know the regular bus had them so I suspect they survived the conversion.) This tray is perfect for helmets, web gear, Enigma code books, etc, etc.
(FYI - Figure painting IS NOT my forte!)
The overall fit of this Roden kit is quite good. With just a little filing and fitting the main body shell can be made to snap on and off without gluing!
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Interior wall bracing, ceiling panel divisions, dome light bases, package tray, ventilator and escape hatch have now all been added to the interior.
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Additional frame members added to the base kit frame are shown in white. This created the proper "C" channel profile to the main lengthwise frame members. To this I also added fuel filler pipe, fuel line, wiring for fuel gauge sender and wiring for rear taillight plus installing drain plugs on the differential, engine and transmission.
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More underbody floor bracing shown in white. (Makes the underside of the vehicle much more visually interesting - and correct - if you are into that sort of thing.):

And what I have heard at times called "duck boards". I can verify that the ambulance buses had them - cannot seem to find photos of the radio bus interior. I am sure the Germans have some long combined name for them translating to something like "wooden structure to prevent slipping on wet floors".

"Wassen stompers"
p.s. To the engine I also added a Verlinden Blitz battery and radiator overflow tank as well as fabricating the voltage regulator, ignition coil, circuit breakers and dip stick. (Sorry but I am not big on doing spark plug wires!)