my favorite feature in the new version of Fogbugz. the only issue I've ever had with it is that if you enter in your parent case and subcases but then find that they are accidentally under the wrong project, the only way (AFAIK) to move the entire case tree is to click on each individual case and move them all one by one. Other than that, I must say it's pretty sweet.
I think the multi-select in the grid view is what you're looking for to make that easy; both shift-select and control select work when clicking on grid rows. Not the easiest thing to find, but really useful.
Yep, tried it and it works. So if anyone else ran into the same problem, just select all the cases you want to move as described above, then click the context menu button and select "Edit" and you can change the properties for a bunch of cases at once. Pretty sweet indeed.