Jonathan Emont notes the semi-thriving campaigns of Ron Paul and Michele Bachmann and argues that changes in media organization and fundraising law are going to make it likely that we'll see more Members of the House running for president in the future.
I think I sort of half agree. He's definitely right that cable news is well-designed for House Members. There's a lot of hours to fill, and that means plenty of guests needed. Someone who makes national publicity a priority is going to achieve it, especially if she's good at the sorts of things that make for good cable news programming. The partisan blogosphere probably helps, too. I don't know that campaign finance law is relevant, but technology probably is; it's a lot easier now to raise money via the use of national publicity than it was twenty years ago.
The other side of it is that the incentives for running have probably increased for back-bench Members. That's also a cable news story, and more generally one about the commercial market for politics, especially on the Republican side. I don't believe that Michele Bachmann is a plausible nominee, but I do think that she's likely to make millions of dollars, if she wants, as a Fox News contributor, "author", and whatever you call the job of being paid lavishly for appearances. Hey, I don't know if that's her plan; as far as I know, she'll wind up back in the House and have a long career there. But the incentives certainly exist.
What I don't think this does is make it especially more likely that we'll get nominees from the House. It could happen, but Bachmann and Paul aren't a sign of that. Unlike previous serious candidates from the House (Mo Udall, Jack Kemp, Dick Gephardt) who had strong reputations as legislators, Bachmann and Paul are much closer in spirit to candidates such as Jesse Jackson and Pat Robertson: factional candidates who can make a lot of noise, and may very well move the party on specific issues, but never really threaten to become nominees. More senior Members -- Paul Ryan, for example -- would be more like Udall, Kemp, and Gephardt, but so far there's no one like that in the race, and I don't think that the changes Emont describes really change much for them.
So, basically, there are increased and increasing incentives in the system to be a Michele Bachmann or an Alan Grayson, and that may wind up populating the ranks of presidential also-rans...but I'm not sure that it's any more likely for the House to produce a presidential nominee now than it was in earlier cycles.