I mounted the tablets on walls with $10 kits from Amazon that use those 3M removable strips to hold the mounts, and drilled small holes for charging cords. I have the screens set to never turn off, and leave the browser open. So all the buttons are always just there on the wall, ready to be pressed. Nothing needs to wake up first.
BTW, Windows 8 8" tablets are now under $100 at Wal-Mart and Best Buy, so you aren't even limited to Android for this kind of thing anymore.