Can you wait about 7 months to make the payment? You could fund a Fidelity account and get up to 25k miles on select airlines, or get 25k AMEX points. You have to keep the funds there for 6 months, but could then pay the mortgage with it. Heck, you could even double your money with the right high risk high reward investment!

That's probably the safest/surest way of doing it, but is pretty slow. You could put the money in a safe fund that earns a few % too, to help offset the cost of waiting to pay down the mortgage.

http://www.flyertalk.com/forum/miles...-airlines.html

The AMEX points could be the best bang for your buck, since you can xfer the points to Delta or BA for 50% bonus.