I am selling a Motorola Lapdock 500 Pro. It has been used for a total of about 10 hours and is in perfect working condition. It sells for $350 on Motorola's website and $300 on Verizon's brand new.
Fully supported phones are the Motorola Droid 4, Droid RAZR, and Droid RAZR MAXX. The Atrix 2, Photon, and Droid Bionic should work, but I believe that they cannot use the webcam, ethernet, or VGA output at the moment (you may want to double check).
I am looking to sell it for $225 shipped. Included is everything originally included in the box: the lapdock, power cable, and manual.
I would also negotiate for a tablet of some kind.