Yeh. I can vouch for TouchDAW too, but I find the complexity of getting it working sometimes a bit much. I've gone back to just using my cordless keyboard which comes into the isolation booth with me when working alone, which is great for everything accept checking levels etc. Thinking of putting another monitor on the wall in the booth so I can see what I'm doing.

(Attempt #27 to post)
 
I used TouchDAW on the Nexus, but in my opinion the MIDI set-up is non-trivial (iOS comes with built-in network MIDI drivers, Android does not).
 
Tobias Erichsen's software helps enormously...and is free. As does installing Apple's Bonjour service under Windows (yup, you need something from "the i-company" to get Android and Windows working together á la network MIDI...unless you like the pain of not having zero-config service detection).
 
FWIW, this page describes the set-up process very well:
http://www.tobias-erichsen.de/software/rtpmidi/rtpmidi-tutorial.html
 
In addition to setting up TouchDAW, I also used the free 64-bit virtual MIDI cable drivers (also available from Erichsen's pages) to plumb in MIDI Doodle to convert the X-Y MIDI information generated by TouchDAW to polar coordinates suitable for sending on to Omnisphere's Orb controller (works pretty well as a substitute for Omni TR).

I tried one of the iPad controllers that are available.  I just tried the free version, I didn't buy the full version.  However, it did not have full Sonar functionality and the PC had to be "on line" (at least on line with the wireless router) to function.  I keep my PC off line when recording (I disable the NIC). 
 
Unless the Cakewalk product is a Bluetooth connection, it will face the same issue of requiring the PC to be on line. But if it is Bluetooth that will require installing a Bluetooth adapter, for many PC's.
 
I would like another wireless option as my Frontier Tranzport is flakey (sometimes stops working and requires a PC reboot to get it back operating).  Whether this is a hardware problem or Win 7 compatibility issue, I haven't been able to determine.  I have installed the Transport in the native Win 7 mode and a Vista compatibility mode and it didn't make any difference, but then Windows 7 is basically just "Vista improved".   The Tranzport is a discontinued product.

I've been using TouchOSC Android for some of my plugins and it works pretty well on my phone. The thing I don't like is that the interface is pretty rudimentary. Something like what OP posted would be a lot nicer to work with because the interface looks professional and clean.