I personally, on a superficial level, am not offended by it. I have ordered it and plan to wear it.

When I first saw this shirt I decided I would have it eventually, because my immediate thought was that it is a statement against the cowboy-as-American-god-hero archetype that I've despised my whole life, and a subversion of the typical swaggering macho cowboy story where the cowboy impossibly pwns everybody, especially the 'dirty, red, heathen' Native people.

All the other blogs I've seen about being upset concerning this shirt have to do with the photo of Threadless models playing "Cowboys And Indians".
But a very few of the comments in those blogs have touched on what's bothering me most: Is this shirt racist? But, both figures in the design are starry silhouettes, so their race can't be proven. So...I guess what I mean more accurately is, what if this shirt was of a cowboy's bullet shooting a Native American from his horse? Would it be more or less acceptable?
What about the fact that I tend to see the Native American figure as a woman (though I think it's definitely intended to be a man)? I doubt I would ever wear a shirt that I thought portrayed a man potentially killing a woman...

(Oh, dear. It feels icky to be faced with your own prejudices, doesn't it?)

Anyway, since nobody's posted a blog like this yet, I'm guessing it hasn't really bothered anybody else, but, in case there is somebody in the 'sphere...I've read a lot of really insightful opinions on Threadless and I'd like somebody to bring some of that to his forum...

So, summation: Does anybody else have any uncomfortable or potentially uncomfortable thoughts on/reactions to this design, and/or the idea/act of wearing it in public, or just on their body at all?