I am the guy Flecs speaks of.....
I have a Webasto canvas sunroof on my xB. Installed for about $1400 including parts. It includes a great warranty against leaks and unlike alot of cheaper canvas roof kits, this one actually has insulation in it to keep down road noise and keep heat in durring the cold months (should you have them).
Some pics........ Oh how I love to pic whore.... lol