Ah, OK. Thanks. I still think it's a MoPar product, although I think the 60's (even the late 60's) may be a little early. And I'm thinking the car has more Barracuda overtones than Challenger. It's a nice-looking design, in any case. Time for some more looking, I'll have a definite guess later tonight if Carnut allows me that leeway.
Never mind - I believe I've found it. It's labeled as a 1972 'Cuda (Plymouth Barracuda) proposal. It's on a page full of very neat designs, some of which I hope we will see on this forum. Too bad Chrysler didn't pursue this styling theme . . . Maybe Plymouth would still be around!