ktulu,
From my experience there is a premium to 'green' a building. Certain systems run higher than others, but typically you can expect a 3% - 5% increase in construction costs. This can vary obviously on the amount of locally or recycled content materials available in the area. Likewise, there are some areas that do not have local subs that can rep certain green roofing systems or other LEED friendly building materials.
Costs to perform any work would naturally vary by region and whether or not the project was union or open shop. While I generally use unit costs that I have established from working with subcontractors, the Mean's guide does have a section in the back of the book that offer ranges of costs of various types of facilities (which need to be adjusted based on the regional factors they provide).
My company just put in a proposal for a core & shell package on an office building (120,000 sf) and all-in costs (including our General Conditions & Fee) was roughly $135/sf. The sitework is always a variable in projects like this and was worth $16.35/sf (SF of the building) since there was a contaminated soil issue. The MEP portion was worth roughly $25/sf.
Mean's ranges for Retail Stores is listed as $58/sf - $103/sf for the 25th to 75th percent of buildings (without any regional adjustment). The MEP range is listed as $13.35/sf - $24/sf.
If you have any specific material costs questions let me know, I'll see what I can do for you.
-Ray
