This is nothing more than the evolution of what Splashtop brought (with nVidia sponsorship) on CES 2012 (confirmed by nVidia Italy itself on Facebook).
Now during the conference it was stated that the client would have reached every android device (not only Tegra ones nor Project shield) and in the next days some hands-on with different "non-shield" devices were recorded.
Finally also the one recorded on Nexus 7 landed (cortesy of Droid-Life)
here it is:
I honestly think that if there will be the option to customize controls other than the only gamepad, the Nexus 7 could be even a better device that the shield itself for this kind of gaming (even if it lacks the Tegra 4 SoC). Furthermore it will surely be a great boost for android gaming in general (thanks to the direct support of nVidia and their money / partners- compared to the influence of Splashtop Inc.). The staff of the Tegra page on FB confirmed me that Grid (that I intend in its incarnation of both LAN (via GFE) / internet streaming (via third party partners)) will have a different timetable than Project Shield, so I think we'll have the opportunity to enjoy this feature sooner than the release of Shield (maybe at the same time with the announcement of the Nexus 7 successor @ Google I/O or even sooner with an open bea )