I'm purchasing a 15" rMBP to replace a 17" MBP that is mostly used for video editing. I edit a lot on-location and travel, and the 15" screen is insufficient for video editing. I'm looking for a good portable USB monitor that I can use as a second screen. Ideally an HD monitor because 1377 x 768 resolution doesn't work well with a retina laptop. I'm interested in the ASUS MB168B+ HD 1080p monitor. There are dozens and dozens of reviews on the net, but I can't find anyone that actually sells it. Any ideas?