It doesn't change the issue, it only puts everything in one place.
There will still be three levels, but you'll have to set them by
editing the INCLUDE/IGNORE keywords at two points within the DTD.
(That could be parameterized, I suppose, but not at much gain.)
I'm working on a 1-DTD version, and hope I can have it ready
by tomorrow.
Regards,
-- Terry Allen (terry@ora.com) Editor, Digital Media Group O'Reilly & Associates, Inc. Sebastopol, Calif., 95472