Several of my colleagues are now looking for jobs in sustainability. Ram points us in the direction of this impressive database hosted by Duke (notably heavy in biological fields).
Searching NatureJobs for "sustainable" also brings up 134 positions at the time of posting. Also see job listings at the Association of Environmental and Resource Economists. Environmental economists can also see this page at Michigan State.
If you know of more listings, please post a comment. Maybe we'll assemble a database if we find enough.