The OS X gl guide recommends against using GL_ARGB textures. Perhaps we should follow their advice.
I don't think it really matters any more, not in a shader world? But it's easy enough to switch -- we already have two sets of shaders, one for rgba and one for bgra (swapped). So we could use BGRA (which is I assume what it suggests you use?) and just swap the shader type, if we're on OSX.
I should've mentioned this earlier, but the reason I looked into this was because glgConvertTo_32<GLGConverter_ABGR8_ARGB8, (GLGMemory)2> was showing up in profiles.
ah ha, so internally it wants BGRA. Should be easy to do, we'll just need to carry around a we_are_in_opposite_land flag (which can be static true on OSX).