With the KFA2 GTX 760, nVidia is arming the upper end of the mid-range with 1152 processors, a 256-bit memory interface and 2GB of memory.
As the name suggests, the MESH Elite G4 760 SLi is armed with a pair of these cards, so you should expect significant performance – depending on the rendering method used by the program/game you're using and how good a profile is available in the drivers.
Measuring purely in synthetic terms, when KitGuru reviewed an Aria PC with a pair of the fastest GTX660 cards on the market, the 3DMark 2011 scores were 12,995 – which gives this MESH rig something to aim for, using relatively standard GTX760 cards.
The GTX760 slips neatly into nVidia's line up for 2013. Historically, a pair of mid-range cards could give the high end cards a serious run for their money. It will be interesting to see what MESH's dual KFA2 cards will be able to manage.