If the OP still is looking for a mixte, why not consider a used one? Solid rides for a third of a new one. I've sold many reconditioned mixte bikes from Northern NJ, to buyers from NYC, Brooklyn, Boston, Phili, North Carolina, Poughkeepsie, Princeton, Long Island, and NNJ. They arrive by car, train, bus, and even ferry!

These aren't IGH, but are fine for charity rides. One buyer recently did a 40 mile ride on her reconditoned 1980's mixte.