I used to know a guy called 'The Mattress Doctor' I met him at a BNI network meeting. He did a demo and we were all very impressed with the results. He stayed for a while and left (just like me). I got the impression he was doing allright but only just. One of the other members had him do their house and was impressed, he was about to go and do a demo for the local Womens Institute but we never got to know the result.
I used to be with ServiceMaster and they had a system for doing that, basicly they put all your soft furnishings everything from your 3pce suite to mattresses in a big bouncy castle type thing in your lounge, put a blow heater on the side and they heat it up to 60degrees, that is the temp that kills the dust mite that lays the faeces etc etc.
But they charge you 10k for the licence!!!!!!!!!!!!!!!!!!!!!
They had a few takers (mugs) but it all ended in tears BECAUSE IT DIDN'T WORK AS A BUSINESS.
I did a house for a customer the other day who had terrible asthma and wanted everything cleaned sanitised etc. I steam cleaned the carpets, severly vacced the mattress's and them steam cleaned them with an iron and a white towel, set on max, this gives you the 60degrees that you need. I cleaned her next door neighbours carpets today who said that shes a lot better since I did the work. I rarely get asked to do it. I don't honestly think there is a full time stand up market for it. You would be better off cleaning carpets. (But not in my area). Ha!