[PTLExp]

Well, I should have probably posted this question BEFORE I went and searched Mackie's forum, and this is what I found (apparently from a Mackie rep):

"In addition to the three DAWs that the C4 currently works with (Logic 7 Express or Pro, Sonar 3 or 4, and Tracktion 2) C4 support is currently being coded and tested with 2 more additional programs (sorry, not at liberty to say which ones). In addition, we're always pestering other companies to add C4 support, as our goal is to have this fine piece o' gear work with as many programs as possible.
However, it is very unlikely that it will ever work with Pro Tools. These days, Digidesign prefers to make their own hardware controllers and does not really work with other companies like us. We were able to get around this on the Mackie Control, by having it emulate a HUI (a product from the days when they did work with companies like us). For the C4 however, there's nothing digi-compatible for it to emulate. Of course we'd love for the C4 to work with Pro Tools, but it's really digidesign's call and there's not much we can do about it."

-I guess the better question would have been:

Hey Digidesign, you guys ever plan on supporting this thing?