Admittingly, a lot of us are confused why these dual GTX 680s boards exist (e.g EVGA's GTX680 2Win Gemini) since there is already the rather dashing GTX 690 (which is also a dual GTX 680 with 4GB of ram). According to our sources Nvidia does not usually allow AIB vendors to release custom designs of their dual GPU cards (GTX590 and GTX295 comes to mind), limiting the amount of differentation among competitors other than price. ASUS's ROG MARS III is decked with the trademark red and black theme of their Rampage/Maximus motherboards, and uses a triple fan heatpiped cooler within double slot form factor, a welcome change from the obtuse three-slot of their DirectCU II cards from past. There are three 8-pin PCIe connectors (implying up to a whopping 525W of power draw potential) present on the board and a red button to activate 100% fan speed for overclocking. For display outputs we get a single mini-DP port and three DVI headers. Sadly, there is only a single SLi connector which limits things up to only 4-way GPU.
The project manager on-site told us that the board we are seeing is still an early engineering sample and that they will still be making some tweaks to its PCB and cooler design before shipping sometime later this year. Since its predecessor MARS II (dual GTX 580) was one of the most expensive and elusive cards ever, we won't be too surprised if the MARS III follows suit.