Another idea:

If you are getting close to an award, top off your account (with Amex, DC, long-distance switching, etc) and cash 'em in through a travel broker. You can get around 1-1.5 cents per mile by selling the awards.

I'm not a broker, just a disinterested observer. For a listing of several, go to http://www.yahoo.com/Business_and_Economy/Companies/Travel/Frequent_Travel_Programmes/