If you're only running a 30- to 32-inch Full HD monitor for games, then you would be fine with a single GeForce GTX 680 - but you mention you want to use it for CUDA, PhysX, Tessellation, 3D and 3D Surround Vision. All of this is very, very stressful on the GPU - and requires more than one to get playable (30-60fps) frame rates in most games.
You mention just one screen, but 3D Vision Surround - which would limit you to 27-inch monitors, and then three of them. If you were going to do this, spend as much money as you can. Obviously two GeForce GTX Titan's would be the best choice - so if this is within your budget, do it.
The GTX 690 cards are pretty crazy - but as you said only have 4GB of RAM. The Titan's 6GB of RAM will be great for the multi-monitor gaming, so you're kind of stuck there. I would still recommend Titan's, but the GTX 690s will give you effective 4-way SLI which would be nearly 50-75% extra performance over GTX 680s in SLI.
Micro-stuttering is very case-to-case, I find I don't experience it - but I am using 120Hz monitors. You would also be using 120Hz monitors since you'd be getting 3D Vision-capable screens, which are 120Hz by default. You might not experience it with 2-way SLI, but if you were to go down the GTX 690 SLI route, the 4-way solution might inhibit problems.