It sounds as if you may have seen an old Mercedes 300SL roadster from the mid-50's to early '60's. You don't see them on the road much anymore. because a good one is worth a half a milion bucks.
1962 mercedes 300sl roadster - Google Search

It would have been interesting if Mercedes had saved the Crossfire styling for an update of the SLK, instead of marketing it as a Chrysler. It probably would have been more successful with a Mercedes emblem on it.