I think the OP is on the right track. If you aren't flying with one of those varios-with-extra-bells-and-whistles that turns into an artificial horizon at the flip of a switch, why not have SOMETHING for emergency use in cloud? Especially if you are already flying with a tablet display anyway, for other purposes? In another thread I made one suggestion, but a full-fledged artificial horizon display is a better way to go, so long as it works reliably. Such a display can be displayed on tablet or whatever and driven by a commercially available AHRS sensor unit. Those units are widely available, as a bit a googling will reveal. Here's one link among many: http://www.aviation.levil.com/products.html .

Of course it goes WITHOUT SAYING that your tablet or cell phone or whatever is going to be rigidly mounted in your cockpit. You certainly don't want to be trying to look at a moving object as you try to control your aircraft in cloud. And it also goes without saying that all of this is for emergency use only.

Me personally-- I still like the simple, completely self-contained nature of the piezoelectric turn rate indicator I linked to earlier, at the top of the related thread "Emergency instrumentation for cloud encounters". I don't want to worry about all this other stuff. And I've practiced enough to know how to make use of the simpler instrument. And as noted elsewhere, the TruTrac is essentially the same thing, just a better implementation and a lot more bucks. But if you were to hand me a tablet running an artificial horizon display, AHRS system, appropriate mounts, fully charged batteries, etc, all ready go, I'd take them and say "thanks"-- especially if the ground were nowhere to be seen!

S