I tried the iPad V Control Pro app, free version, as I have been looking for a wireless replacement for my Frontier Tranzport which appears to be on its "last leg".  V Control works but it seems more a gimmick than a working controller, at least in Sonar.  Installing the "Ney-Fy" control program and its associated MIDI devices caused my iLok to not function (I got a message that I couldn't be enabled on multiple PC's at the same time).  Uninstalling the Ney-Fy and the associated MIDI devices it installed fixed the iLok problem.
 
In addition the V Control had to be set as a Mackie controller in Sonar and I had to uninstall my BCF2000 controller for the V Control to work.  Another negative, at least for me, for this program.
 
I have a thread in the Hardware section about a wireless controller replacement but after searching and talking to my sales rep at Sweetwater there is nothing currently available (Frontier is out of business).