One alternative term that might work is "Mainline" media-in reference to the practice of injecting heroin directly into veins. MSM really is the modern equivalent of what Marx referred to as the "opiate of the masses".
The term that I think has a bit more precedent is Ralph Nader's phrase "corporate pornography". That really explains a lot of the peculiar bias of the media in the US.
Immigration restriction is ultimately a populist issue. Immigration was loosened in the US not because of an overabundance of democracy, but because of systematic over representation of specific groups due to campaign finance practices illegal in most countries, peculiarities in the US election system-and concentration of media power. No truly representative body would have approved immigration expansion even with the power of money and media.
We writers on VDARE.com need to quite being so nice to the purveyors of corporate pornography. There is nothing "mainstream" about these folks. They simply aren't deserving of the term MSM. Corporate Media might be a little less offensive term-but largely these publications and broadcasts are infomercials with pretenses of journalism, particularly when it comes to immigration coverage.
I suspect the immigration issue will really start to get resolved when we see films with an attitude similar to Super Size Me or Sicko directly addressing immigration. Fast Food Nation made a stab in that direction, but we need material that more directly addresses the issue of immigration both from a fictional standpoint and documentaries-and which maintains a strong, "in your face" anti-corporate stand to be truly marketable.