Interesting theory. That would require, at minimum some state to go for a 3rd party. Otherwise in a 2 person (electoral college) vote one of the two will certainly get the majority. (Although technically a 269-269 tie is possible.)
Gary Johnson is at about 18% in New Mexico. 3rd place. I don't see him pulling out the win in his home state, which would make a "no majority" Electoral College more possible.
regarding House of Rep. possibility:
The odds are better (though very low) that this happens due to an exact tie, 269 to 269, than to Johnson winning anywhere. Romney states + FL + OH + IA + ten more EVs = 269; ex., NV and NH; or, WI; or CO + ME-2.
There’s that Mormon ex-CIA guy that is hoping to pull off Utah. Of course, there are some funny combinations needed if Utah’s electoral votes will be enough to put it in the House.