I have found three other companies making garment pannier bags since I ordered my Nashbar one. Two of them (Performance Bike and Transit Authority) are the exact same bag as the Nashbar one with different badging. Performance's price: $99, Transit Authority: $150. The third Jandd is $224 and is single sided. I don't see that it is available in any case. YMMV, FWIW.
H