Anyone ever seen one of these?

Yes, friends of ours had one years ago, very similar the OP's vintage but was red. It had a V8 (I think the 345) and, get this, a factory 5-speed manual transmission. I always figured it was a rare bird, especially with the 5 in it. The owners just used it as the work truck it was built to be, and I regret not letting them know I'd like to purchase it when they got rid of it. It's long gone by now.