Do you have miles with another airline? One option people tend to overlook is going one way with BA and the other with someone else. I've done that twice this year (BA from LHR, CX to HKG) and filled in the return flights with United miles, which I had a lot more of to spare. It also helps that ever-frequent situation where one airline or alliance always seems to have seats to get there but not back.

100K miles would get you two one-way business seats to LHR or Asia from the U.S.