As I am sure you are aware, there have been problems with homeowners who could easily acquire a loan but then had trouble paying. http://www.hud.gov/
Web Reference: http://fhamortgageinfo.com/
YES, there are 40 year fixed loan programs but they are not FHA. I know of a local Maryland BAnk that will offer you a 40 year loan and you can get 100% financing with them. Although it breaks down to 40 years on the 80% loan and 30 years on the 20% loan. Thisis not a CDA product as mentioned in the other answer. Let me know if you would like the name and number of the contact at the bank.
If you are a first time buyer, I would recommend looking at the Maryland Dept of Housing's CDA loan program, which does have a 40 year program and lower than market rates. It also has flexible approval guidelines, much like FHA. The website for it is http://www.MoreHouse4Less.com. This program is truly my specialty, and if you have any questions, feel free to contact me. I also post a lot of info on it on my blog: http://www.ThoughtsAboutRealEstate.com
Best of luck in your home searching!