While I cannot answer on the feasibility part (in terms of security feasibility), I do however think it's a really good idea.
Devices are getting smaller, touchscreens are right now spreading year by year at a faster and faster phase. We are seeing small raders, lasers and cameras which tracks hand or body movements. Google glasses and similar technology had a fallback as the tech wasn't ripe in society yet (privacy concerns, lacking apps, too weak at the time, etc.), however it will most likely soon be back.
I just want to ask the question, what will happen when our phones are strong enough to effortlessly run any workstation or any job a desktop computer can do, and combined with the technology mentioned above, and the Linux world is behind?
To me, it looks like Linux (and Qubes for that matter) will be heavily disrupted in the near future, if we do not take these emerging technologies seriously. Qubes might still have its security strengths to rely on, but in the face of awesome new convenient technologies like these, that will be the only thing keeping it alive.
We need proper touch, VR and graphics support in Qubes (and Linux in general for that matter). It may not be important right now, but it will be in the near future. It's a long-term investment (in time and coding) to build the infrastructure of tomorrow. We might risk having the ground shaken under us as these new disruptive technologies will kill off laptops and tablets (and desktops for that matter).
Think of it like how Apple disrupted all the traditional mobile phones, and how naive everyone were back then. Try google them up, how arrogant these people were mocking Apple's first iPhone. Yet the very same people who mocked them, came to fail tremendously because of Apple's disruption. I'm no Apple fan-boy btw, I stay clear of Apple devices, however it's a nice example. Another similar example is Kodak and the digital kamera, ironically Kodak invented the digital camera, but didn't believe in the technology and shelved it. Then they were disrupted by the very technology they created by other companies.
The visionaries will always win the game, because they are always several steps ahead of everyone else. Linux (Qubes) need to pick up our game, or yeah, it's gonna be some tough years just trying to catch up.
Perhaps I see the coming years wrong, but the way I see it stands right now, we definitely lack development in this area. The year of the Linux never comes, because we always, always play the catch up game rather than taking any leading positions. Where is our visions?