Richard Green says that they are believed to be of the same status as R.O.U.S.:
Richard's Real Estate and Urban Economics Blog: The real problem with John Taylor's paper...: ...is that it asks the wrong question. The issue is not what would happen to rates without the Fed backstop to Fannie/Freddie, but whether there would be fixed rate mortgages at all. 30-year-fixed rated-80-percent-loan-to-value mortgages beyond the conforming loan limit basically do not exist at the moment. A conversation I had today with two bank executives confirmed this. Some would argue that 30-year fixed rate mortgages are over-rated, but not I.