Back in the 70's, the world almost saw a super powered character called the Black Bomber. He was supposed to be a white racist that, in times of stress, turned into an African-American superhero. This was due to chemical camouflage experiments he participated in as a Vietnam soldier. In some of the scripts for this character, he was actually appalled after having risked his life to save some Black people and even made racial slurs. The whole idea of this character was absurd and thankfully, the character never actually saw print. What we got instead was the DC Comics character called Black Lightning. You can read more about this here.
Just recently, in the pages of the Justice League comic (#26 dated Dec, 08) the earth went through and out of a quick revision. In that new universe that lasted for half of two issues, a new character appeared called the Brown Bomber. He is apparently a Caucasian that upon shouting the phrase "Black Power!" becomes an African-American (hero?) complete with afro, gold chain, and medallion. He makes a couple of racial remarks and explains that his powers last for only an hour which is not unlike the character Hourman. The writer, Dwayne McDuffie, is himself and African-American, and has had a big role in the creation of African-American superheroes including Static. I have to say it was interesting to see this character in print but I hope not to ever see him again.