As for videos I would like to see:
A walkthrough of a truly transformational remix. Something along the lines of taking a ballad and turning it to a dance track. I think that would show off a lot of tools within Sonar. Things like time stretching, melodyne and effects would be on display beyond the theoretical.
A video focused on staff view. We see a lot on this forum what the staff view can't do. Perhaps showing what it can do with some detail may be of use. This video would include some practical workarounds for nagging issues some may face.
A series of genre based tutorials. Any DAW can create any style of music, but sometimes it is hard to see that when it seems so much easier with more specialized DAWS. I know this may draw some groans, but a "Creating dubstep in X3" video may not be a bad idea. Susbstitute "dubstep" with any other reasonably popular genre and you get the idea. This may be too large of a task for Cakewalk alone since there are so many genres, but user created content may work here. I can see why you would be reluctant to go user created ones as chuck suggested, but I'm sure there's a middle ground. Perhaps a contest along the lines of "Create fantastic X3 tutorial" and win some small prize. Publish only the winners and categorize them. So many possibilities.
Best practices videos outlining the less exciting to some but very practical topics like gain staging, controlling phase, harmonics and how to fix problems with such things in Sonar. i realize that it's not Sonar's responsibility to turn everyone into a master audio engineer, but some quick tips may help the hobbyist immensely.