Ummm... find a couple of DL Cards (I believe there is currently an offer for DL amex plat for 40k).. if you manage to open a business AND a personal one, this should be 80k miles...

AMEX membership rewards is always running a bonus of sorts as well

OR... you could find availability on DL partners Air France, KenyaAirways, and KLM that would let you redeem miles at the low level...

175K extra sounds like a LOT of miles.

I would never *buy* them. you're better off putting this kind of cash toward a YBM fare and using miles to upgrade...