that's not what i meant.  given the existence of the vnode switch, and the
primitives contained therein, there is no big obstacle to writing a vfs/vnode implementation
that converts the operations within its scope into messages on a file
descriptor in much the same way as network file systems were implemented
by 8th edition, or by me in my re-ported Unix kernels for the VAX and Sun-3,
using a simpler file system switch.    do just one of those and you can have as many
things as you like outside the kernel. 

having said that, it's hard to know quite where to start with some of these
new improved switches.  whew!   just look at the size of that one...