Sorry to be a pain. I've just read "Interfacing Userland with the Kernel"
by Bruno van Dooren (http://haiku-os.org/learn.php?mode=nsl_view&id=25#90)
and it mentions a set of tutorial driver projects. Unfourtunately the link
to the zip (http://www.beunited.org/downloads/DD_Tutorial.zip) is broken and
after doing some snooping and Googling I still couldn't find it. It doesn't
appear to be on BeBits either.
I'll see if I can find the tutorial projects tomorrow. I should still have them somewhere.