On the question, "Why isn't there a Malcom Yellow?" I think a number of factors contribute. First and maybe foremost is the cultural trait of APAs of community/family first and how this manifests itself in politics. There are many APA activists, but they travel in packs---the Committee of 100, OCA, JACL, you name it. Collectivism is the way. In some other cultures, all you need is a pissed off person and a microphone.
This relates to reason #2: the aversion to being singled out, for good or bad, as this relates to notions of "face" and controversy. I have a good friend who is female and SE Asian, a former news reporter. She said that they would often try to get Asians to speak on camera but that it was very difficult. When she said that, I could relate because I was once asked to answer a completely innocuous question for a news story ("Do you think a street should be named for Cesar Chavez?"), and I told the reporter I didn't want to be on camera. Some Asian cultures believe getting your picture taken is a bad omen; in my case it's just nerves and the certainty that I'll look goofy.
There are many other factors---the residue of the model minority myth suggesting Asians just be quiet and study or work hard, the hesitance of society to trust an Asian male, etc.
This leads me to some freewriting/thinking on Jenn's question, "Who would it be?" I think sexuality and religion are not as important as other rhetorical qualities such as ethos and pathos being strong in the person. The person would have to be palatable to the general public, articulate and intelligent, versed in the many Asian cultures' struggles.
I also wonder if the ideal person would be a woman. Case in point---during the Vincent Chin murder trials, the most visible and outright activist was Helen Zia. She was on the news, talk shows, and in the papers. Some of the most activist and outspoken literary people in the APA literary world are women---Jessica Hagedorn, for example. Many men, particularly of Japanese descent, have had to depoliticize to survive the anti-Japanese sentiment of the 1940s, 50s, and 60s (and to the present for that matter). Women are also more palatable in the media (in my opinion)---take, for instance, the large number of APA women in news journalism, as opposed to male anchors. Yes, of course this stems from White caricature-like racist creations like Charlie Chan, but the residue is still there. A woman would surely face a lot of heat---what spokesperson doesn't?---which relates to another prereq: the ability to take a lot of heat, criticism, and threats.
As far the issues that unite, of course there are some. The ones posted here, however (the glass ceiling---or, as the great new book title calls it, The Bamboo Ceiling) are not going to galvanize a community (APA or otherwise) in my opinion. All the issues are important, of course, but they do not resonate as much as farm workers not being given water or African Americans not being able to eat in certain restaurants. But the "hot-button" or mainstream ones are where a voice would be helpful (Abercrombie, Miss Jones, Sony Playstation)---as would the APA civil rights that are violated throughout the U.S.---especially, in my opinion, with regard to civil rights being trampled upon, such as Wen Ho Lee's eight months in prison (solitary confinement, no less) without ever having been charged with a crime.
And, guess what? The person who created and led the Wen Ho Lee National Legal Defense Fund? Cecelia Chang. A woman.
But woman or man, tall or short, I am optimistic that in my lifetime I/we will see this galvanizing force emerge, making things a little better for all of us.