I've used a "Mini DisplayPort to Dual-Link DVI Adapter" to drive a single Cinema 30 from my (2014-era) MacBookPro11,2 before. Can I hook up two of them to drive a pair of Cinema 30's? It's got 2 Thunderbolt ports and 2 USB ports, but the USB are on opposite sides -- will the USB cable reach? (UPDATE: The cable will reach, but it's pretty tight. I wouldn't want to plug/unplug it a lot.)
Is the USB plug just for power, in which case, could I plug it into a different USB port? Or is it needed for extra data, too?
Alternatively, is there a Thunderbolt dock that supports this? The docks I've looked at so far say they don't support multiple displays, but they seem to assume a new Thunderbolt display, so it's not clear. Dual-link DVI is kind of an odd beast.