Ok, a few observations now that I\'ve had a chance to play around with several configurations.
First, having pdaXrom on the SD is great, especially for a C750 owner, with a 256 SD card, I can install what ever I want without worrying about space.
Using the Cacko 1.21 kernel will work as long as you use the Xfbdev file from x11zaurus that Stu posted. While it works, it doesn\'t work well. The calibration is off (I think because x11zaurus was meant for the portrait orientation of the 5x00 (the calibration screen\'s text is in portrait). Also suspend, power buttons, on the fly rotation and wireless don\'t work.
I flashed the pdaXrom kernel (while still keeping Cacko 1.21 ROM in internal memory) and the original Xfbdev works fine, calibration is spot on, rotation works, wireless and power button all work. It is however, noticibly slower than with Cacko kernel. And of course with the pdaXrom kernel, Cacko Qt is wacked. It runs but the calibration is so off it is all but unusable.
Conclusion, for this to work well the kernels of Cacko & pdaXrom need to be more compatible. Next I\'m going to try derek\'s suggestion of comparing output of ksyms, but my shallow linux skills may not be enough to make much of them.
Jerry