These could be great to use with iC Pro.
Can be used with both iOS and Android.
Real knobs to on your iPad or Android tablet.
Check them out here:
The Tuna Knobs Kickstarter campaign kicks off on 7th July. 
Interesting concept!
From a product page:
They are made from clear high end Lexan combined with a soft touch and conductive rubber like material that mimics your finger while turning.
Each knob has a separate axis with a small but powerful suction cup so it connects to your screen.
The little nodule on top of each knob might be for pushing to activate the suction.
If course, with iC Pro, changing to the settings screen is a real problem. You would have to have another device, like a phone, to do that.
Since most modern touch devices only have 10 touch points, there can be only so many of the knobs that can be used on one device. Also, each knob used means one less other control (non-knob) control that can be used simultaneously. That is, each knob reduces the available touch points by one, so 10 knobs means nothing else can be used.
Also, 11€ for a knob? Especially since they are not that complex. Price of innovation. I suspect that if they don’t drop their prices real quick, there will be much cheaper imitations appearing soon.
They could do a similar thing with a slider, but it would have to be adjustable in length.
Their stuff would be useful on a touchscreen for use in Cubase on Windows, but unfortunately it is touch-dumb, and probably will remain so until SB stops limiting functionality (and their thinking) to only what Apple allows.