In case Gilt Groupe, Ideeli, Haute Look, Rue La La, and Row Nine weren't enough for you, now there is Mintbox. The latest entrant to the sudden proliferation of designer discount and sample sale sites aims to trump them all by providing "extraordinary perks," which are to include by-invitation-only sales on current-season merch and 5% cashback on all purchases. Having sufficiently piqued my interest with a promising roster (Alexander Wang, Givenchy, and Rag and Bone are among the names dropped), I'm very much looking forward to finding out what kind of deals can be had. As of now, it's by invitation, but you can gain access by using code AAMB5 at signup.
UPDATE 12/8/09: Whoa, this is even better than anticipated. In today's Racked:
One of this months deals from Mintbox: shop at NYC's own Otte boutiques in-store or online now until the end of December and receive 15% off all full-priced merchandise plus 5% cash back back to your registered credit card. Mintbox also provides access to private events, New York fashion week shows, and designer previews/trunk shows.