I think it was the Superman animated series (and later JLA) which sort of mixed the original concept with the look of the Linda Danvers version. They of course eventually brought back a post-crisis version of the original Kara (In Batman/Superman) who has become a staple of the post-crisis Superman mythos since, although with the relaunch I think her origin has been altered (Along with Supes himself). I think in Justice League Unlimited, the DCAU version of Kara also started wearing an outfit similar to her comics counterpart.
There's also of course Power Girl, who is the cousin of the Golden Age Superman who lived on Earth-2. But that's a whole new mess there, too.
Plus wasn't there a Jeph Loeb or Joe Kelly version of Supergirl as well, who was not blonde but had dark shorter hair? I think she showed up in a strange Batman/Superman story where all the different incarnations of Supergirl teamed up.