Jonathan Frakes as Captain America - Really

It was recently pointed out to me by Alan Kistler* (he knows things) that Jonathan Frakes was employed by Marvel in the seventies to make appearances as Captain America at conventions. He was, of course, in costume.

Image from Plaid Stallions

There's no positive proof, but this seems to be Jonathan Frakes. The chin cleft matches. This image could be him, too.
Riker was Captain America. Mind blown.

*P.S. Alan writes a fabulous column at Newsarama about superhero fashion: Agent of S.T.Y.L.E.