Hey huys, I have had all kinds of struggle trying to use this feature (shared textures, particulary DX texture -> OpenGL app like Resolume Arena in my case) on my Optimus notebook (Lenovo ThinkPad T420).
I have tried all the possible graphics driver settings I could imagine, with no luck.
BUT, just by a lucky accident, when i brought my machine to a friend for cleaning and other maintanance, as my friend knew I was struggling with optimus, he suggested to take a look at the UEFI BIOS settings, to check if there is a possibility to disable the integrated Intel graphics on that level.
And voila, just after updating my UEFI BIOS, we found it was possible to do so, just to selectively and explicitly enable / disable either of the graphics cards. So I just disabled my Intel graphics and boom - even the original Elios DX texture sharing started to work like a charm;)
Although a am aware this is not an optimal solution as I cannot use my Intel, it definitely worked for me, unlike any other solution.
So I would encourage you to buy an optimus laptop, as long as you make sure it BIOS / UEFI or whatever system setup it uses, allows you to selectively disable particular graphics. Hopefully nVidia is going to fix this on their side too soon - I believe so because the pressure from user communitiy seems to be quite massive:)