You can go ahead and try carving that thing but it's going to be a complete mess. It might not even compile.
Out of a certain morbid curiosity though, I did make a hollow sphere out of only triangles.
This is NOT a good idea. BSP is about blocks not individual triangles.
But anyways, here it is:
Updated SuperJer Object Library:
http://superjer.com/lies/SuperJer.ol
Just DO NOT expect it to work out all peachy.
Do you just want a spherical room? But with no walls on the outside? That can be done somewhat safely if you just turn my hollow sphere inside-out.