The "Choicelist Database Query Protocol" you refer to at:
http://www.choicelist.com/Personal.html
... would be a kind of consent protocol as defined in section 2.5
of the ASRG framework.
Choicelist could be one of the implementation options available
in a standard framework, or else could become part of the
standard. If it is as powerful as you suggest then perhaps the
work on XML-CPDL ought to define standard test(s) for checking the
Choicelist status of a sender.
I didn't actually catch the big picture the first time i read this.