It appears that this all came out of Kurt Wimmer's head (he's the writer and director). When asked about where he got the story in a 2003 interview, he said,
The movie is basically (John Cassavetes') Gloria told in the future... [with a few other differences]
[Note: Along with that interview, there are a number of comic-book-looking storyboards.]
Greg Dean Schmitz over on Yahoo! references a Variety article that mentions:
Kurt Wimmer wrote the role of Ultraviolet specifically for Milla Jovovich...
I found a similar quote over at ign.com (referring to the Variety article):
Wimmer, the trade says, wrote the script with Jovovich in mind after seeing her in Resident Evil.
Apparently, the movie wasn't even originally called Ultraviolet. In a 2002 article, Fangoria reports on Wimmer's "sci-fi vampire project", quoting Wimmer:
It's called VALKYRIE, and that's the lead character's name...
None of this completely precludes that it could have been loosely based on an obscure comic, but I would have to say the lack of evidence points toward that.
I don't know where the whole "comic book" relationship came from but I guess it's possible that it had it's genesis with this (horrible) FilmJerk screenplay review that I've seen referenced in a number of places. From that review:
Dialogue, characterization and the settings are all spotty, as it plays out as something more suited to the comic book or videogame form than a major motion picture.
Besides that, all of the production art I've seen for the movie looks like it was something that was printed in a comic book. [*Note: this sentence sounds like I was saying the concept art was bad enough to be found in comic book; actually, the art is very good - I just meant to note that it had a very comic-book feel to it...]
I think I'll follow up with all the comic book movie sites and see if I can't get any more info...