Vacancy sensors are a great idea and I would like to hear more about any
actual studies that quantify typical diversity reductions. When performing
energy audits, we regularly encounter people who prefer low ambient light.
Standard occupancy sensors would be a real drag for these folks!

Here's a great source of lighting study white papers, including a good
analysis of the differences between ASHRAE 90.1-2007 and IECC 2006 w 07
Supplement: http://www.aboutlightingcontrols.org/education/index.shtml.

For Massachusetts readers, please be aware that the 7th edition of 780 CMR
that was released in September 2008 was superseded by a more restrictive
code in October 2008 that uses the previously mentioned standards. This was
a recent surprise to us as well as others I've spoken with who need to be
aware of code minutiae. Here's the link to the new code:
http://www.mass.gov/Eeops/docs/dps/inf/780_cmr_13.00_energy_efficiency.pdf
(bonus - the wonky formatting makes it an interesting read). Interestingly,
the basic requirements of LEED EA Pr 1 appear to be required to get one's
Certificate of Occupancy (MA specific addendum to section 104.5).

Eric