Hello Fredrik,
Thank you for the kind words; glad to hear you are enjoying your experience with SpaceClaim.
To address your questions:
1. You may be looking for the "Show World Origin" option on the Display tab. This will place an origin at the world 0. This is obviously not the cPlane you want, but you can easily create a Datum Plane from the origin. I will pass along an enhancement request to Development for the world cPlane.
Also, in the Service Pack we are expecting to release next week, we have introduced the Set Spin Center command, which should help you to keep your bearings when rotating the model.
As far as moving the sketch grid with the standard Move tool, there is a Move grid Option under Move, as well as a button on the mini-toolbar (found by right clicking), which may help you move your grid faster.
2. While we do not currently support 3d point creation, we are adding the ability to "Enable XYZ Measurements" in the Measure tool in SP1. This will display the difference in the X, Y and Z directions between two selected objects.
3. Once again, you are describing functionality included in our soon to be released Service Pack. The workflow is slightly different than you describe, however. To create cylinders from a series of curves, you will simply select the curves (or edges) and then hit the Cylinder tool, at which point you only need to enter in a radius and SpaceClaim generates cylinders (or swept tubing) along the curves.
I think you will enjoy these and a number of other enhancements in the upcoming Service Pack, and we always appreciate new suggestions for improving the product further in future releases.
Regards,
James