I don't actually use the word "Corporatist" very often, but that's exactly what Ron Paul called Obama and that's exactly what he is. Technically he would be a fascist, although people don't like that term because it makes Hitler appear in their heads.
I'm occasionally disappointed on RPF when someone who I agree with philosophically like 95% of the time calls Obama a socialist. Its completely inaccurate, and it makes us look like Palin clones (Even though Palin would be, admittedly, less bad than what we currently have
). Libertarians are not conservatives, and the use of stupid rhetoric doesn't help fix the false perception.
I wouldn't call socialists and corporatists opposites, although that's only because I look at the political spectrum as more "Total government on one extreme and no government on the other" more so than "left vs right." Both support government intervention, and lots of it, it just depends on for what. Free-marketers are opposite of both.