I'm gonna sort of piggy back on KMG's comments. First of all, i dont want to knock your DIY spirit, but i think the problem is that even thought RHP's and CHE's both use IR to heat the cage, they work in different ways (wow, that was a lot of acronyms!) Full disclosure: I do not know how RHP achieve their heating results with such low surface temps, and i surpassed my 5 minute google limit researching (its a forum post, not a term paper, right?) But basically, and i think this is what KMG is getting at, just because a RHP heats effectively with a low surface temp doesn't mean a CHE will also heat effectively with the same low temp.
Or maybe that is not what you are getting at at all.
Again, I'm really not trying to dump on your idea, please tell me if there is something that i am misinterpreting here.