Oregon developers Interface Engineering managed to design and build the Center for Health and Healing at the Oregon Health and Science University to meet (and even exceed in some respects) LEED Platinum standards -- and do it on a budget no greater than that required for a conventional building. Moreover, they've decided to make the details available, for free. The 48-page Engineering A Sustainable World tells the story of the building project, and provides insights into how to create and build environmentally-friendly structures on a limited budget.
The book can be ordered through the Interface Engineering website; unfortunately, they apparently have decided not to make it available as a PDF download (which, frankly, would have been the ecologically-friendlier approach).
I've emailed them directly requesting a pdf copy of the publication. When they respond (likely after the holiday on Tuesday), I'll let you know. If they send me a pdf, I'll post it at Watthead and send you a copy.
Just a note: Interface Engineering is not the developer on this project. That would be Gerding/Edlen. G/E has quite a bit of experience with LEED in the Portland area, much of it with Interface Engineering on the design team.
My suspicion on why you have to contact Interface to obtain a copy of the case study is that green/sustainable/high performance design is still new enough that firm differentiation is the first order of business - even if you believe sustainable design is the "right" thing to do.