I saw a couple of these at Portland this year. They pass muster with someone that is not familiar with Simplexes, but are very easy to spot for someone with some knowledge of simplexes.. The frames are pretty close to stock, but the rear dropouts are made differently. No belt drive is a dead give away. The front end is slightly different, and the front suspension rockers are not a nice forged unit, but a flat plate arrangement.
Why he used a triple tree style for the handlebars is beyond me. Same with the minibike style throttle control. It seems to me, he could have bought some reproduction parts from Wayne and had a far more convincing replica.
That said, I like his fenders and gas tank! No rust fiberglass would be a nice option, as these are getting hard to find in decent shape.
Bob, is he still building these?
Rick