Here are some links and content I distilled from a quick search through forum threads/posts:
http://blog.cakewalk.com/new-v-control-pro-ipad-controller-for-sonar/Novation Automap
http://saitarasoftware.com/Site/AC-7_Core.html "adding wireless problems" - If you're concerned about this, you can use the AC-7 Core wired instead.
It needs a few extra bits and pieces though... The connection goes:
iPad -> iPad Camera Connection Kit (USB) -> USB to MIDI cable (M-Audio Uno or Cakewalk UM-1G for example) -> spare MIDI In and Out on your system
It then functions the same as a hardware unit with no wifi latency etc.
http://level6productions.com/ I (not me but the guy who wrote this) have eyoControl, V-Control Pro 1 and AC-7 Core. All work well.
(V-Control Pro 1 doesn't use rtpMIDI, they have their own sw for that)
Anyways - I hope something in the above fits the bill for you. I would imagine by now there are a bunch of other control apps, as well.
Bob Bone