In ASHRAE 62.1-2004 user manual, Appendix A addresses multi-zone recirculation system along with single zone systems. Most probably multi-zone systems with DCV should be addressed in 2007 as well (or continued into 2007). Interestingly enough, I just saw this link for a free download of ASHRAE 62.1 with LEED Registration.

http://www.usgbc.org/News/PressReleaseDetails.aspx?ID=3824

Hope that helps!

- Gunnar Hubbard, Fore Solutions, LEEDUser Expert Reviewer