It looks like you're new here. If you want to get involved, click one of these buttons!
Nvidia says that Maxwell, their next generation GPU architecture, is due out in 2014. They also introduced its successor, Volta, though they didn't predict a year. 2016 seems like a good guess. Nvidia said that Volta would have stacked DRAM, to get a good amount of memory closer to the GPU rather than having to pass through a normal video memory bus. Not all video memory is accessed equally often, and having some tens of MB available to store the highly-used framebuffer and depth buffer can be beneficial. One variant of Haswell will do roughly that in a few months. Rumors say that the next generation Xbox will do so as well.
On the Tegra side, they're promising Tegra Logan due next year, with a Kepler GPU. That should finally mean modern graphics in Tegra, as opposed to the architecture from 2005 that they used in Tegra 4. Presumably Kepler wasn't ready in time for Tegra 4, and Fermi was way too high power for the mobile use that Tegra is built for. Tegra Parker should come the following year with a Denver CPU (that's Nvidia's custom ARM cores, rather than off-the-shelf like Cortex A15) and Maxwell GPU.
As for Grid, they talked about the high end Grid K2, but not Onlive-style gaming. It sounds like the goal is to have a ton of GPU power available over a LAN for various professional graphics and GPU compute purposes. If you're going to buy 8 Grid K2s and put them in a box, then the price of that is probably well into five figures, so shelling out for 10 Gbps Ethernet or some other such high bandwidth LAN connection doesn't seem like such a stretch. Furthermore, it's virtualized, so you can have 16 people connected to a single box simultaneously, with each taking more or less of the GPU power as needed.