Okay, so it’s not a badge, and it’s not from an automaker, but Hurst did supply the automakers with shifters during the muscle era, so it’s close enough.
However, I do have a standalone H from an automaker: If you’d like to challenge yourself, take a look at this H and tell me what kind of car it adorned. Once you’ve done that, send along pictures of any other standalone Hs you know of, as Hugo90 did with another H hubcap in the Hemmings Nation Flickr pool.
UPDATE (22.April 2010): Stanley Glemboski of Suffield, Connecticut, brought out his 1972 Honda Z360 to the Charles Gould microcar show last year, where I snapped this full-size photo of it:
If only we’d been playing this game back then, and I’d have captured another letter off Stanley’s car!