I'd think the easiest would be to make a script replacing www.washingtonpost.com with mobile.washingtonpost.com in all of the html files that are in ~user/.feedingit/XXX.d/ where XXX is the hash corresponding with that feed and run that automatically, or manually, before reading.
Adding a line or two in rss_sqlite.py to do the replacement there at download would also work.


@SaintGermain: I'll be looking into that shortly, haven't had a chance yet.