I'm not sure that I have heard any other Part 15 broadcasters. I do recall hearing one supposedly Part 15 station run by a high school near Baltimore, but shortly after several DXers reported hearing it, it went off the air, the rumor was it was not exactly Part 15 compliant :-)
IIRC WMCR (which AFAIK is not an FCC issued call sign, I think WMCR belongs to a station in update NY) claims a 6 mile range on their website, which does seem excessive for Part 15.