Long time Cakewalk user (12Tones) and remember the CAL scripting language, which still hangs on.  I came across this Lemur app for my Ipad and was going to explore this as an interface for my SONAR.  I want something more than... start, stop, record.  I was thinking more along the lines of Stephen Kay tweeks, the father of karma; arpeggiators, triggered effects, the works.  Before I get started, have any of you tried this with any success, if so, please do share.  Thanks!

I've looked at Lemur before and your post caused me to take another look at it. I took a look at their user library and saw a Mackie/ACT app for SONAR, as well as many interesting customizations - a ton of synths, (Sonic Charge Microtonic, Rob Papen Blade), akai beat box emulators. All neat, but my big concern would be how easy it would be to go from one to another without locking lemur into being a one trick pony. There are already a lot of Mackie emulators for the iPad, which it sounds like you are most looking for (control surface). I personally might be interested more in a controller for the SONAR step sequencer or mod matrix - there are lot of similar examples for Ableton Live. Otherwise AC-7 fills the Mackie niche for a lot lower cost than Lemur.
Please post back with your experiences, especially if you find something you really like, or if you develop something. Are you intending to connect via wifi (I don't recommend) or with a plug in midi I/F?

Sure thing Brando, I might not have stated clearly, I'd like controller functions as well.  After the setup to get everything talking (in&out), I'll focus on the poly functions.  Seems like you can create custom screens pretty easily. We shall see. 

Good luck! Love to hear how you progress.