Would it be terribly rude of me to ask "Why?"

You're right Danny, an 8' body/chassis plug and converting from the 440 gasser to a diesel makes this
mod almost incomprehensible from a practical standpoint, not to mention $$. Makes me wonder if this is a
one-off manufacturer's prototype.....It was the era when top enders like Bluebird, Newell, etc were growing in length and bells & whistles.....Maybe a desperate attempt at gaining market share

Danny, sometimes the answer to your question, particularly these days, is 'Because they could'. It is really pretty neat looking, though.
Jim