Yeah, I have to agree the CC on XM family doesn't include a lot of diversity. Even KISS XM, which is CHR/Rhythmic, and does play a fair amount of African-American & Hispanic artists, is not really urban-focused, because they play many dance mixes of pop songs as well, so they do have a more "mainstream"/Caucasian interpretation of Rhythmic. I do think it's a somewhat interesting CHR, as very few stations will actually play dance mixes *only* on certain pop songs. These mixes are often not heard, or not heard frequently, on any other XM channel, so it does liven up KISS 21.
A wildcard idea is a Christian CHR (I know, another white-bread format, but hear it out.). CC's Format Lab did contain such an animal at one point, and it is a format hole on XM, as The Message definitely skews older toward the Inspo/Worship side of things these days. The one at Format Lab, "Hits on High" contained Christian comedy clips, short Bible verses, etc. so it was not just wall-to-wall music. They also do have at least one terrestrial station in a similar format, Shine 96.7.