I’m guessing and hoping the “our” in your last paragraph pertains to Cleveland, yes? Outside of the Maple Fund, I am not aware of any VC Fund that targets “CleanTech”.
As far as CleanTech representing the next pile-on opportunity for investors — why wouldn’t it? If CleanTech is even remotely related to Natural Capitalism, the technologies and practices developed for doing business will save tons of $$ because they directly address external costs - environmental and social costs for example. Consider how much environmental litigation would be lessened by simply removing petrol-based pesticides from mass-agriculture or removing VOC’s from paint. I’m not sure these examples even represent low hanging fruit, but you get the picture. How can investments in CleanTech not be a success?
I suppose that question is based on one’s defintion of success, which is precisely where CleanTech may differ from Natural Capitalism.
In my mind the more pertinent question is, how can this region get onboard with CleanTech as the resulting products are certain to have global appeal. We have the proficiency in manufacturing and polymers, but what is our motive? I would humbly suggest that we begin thinking about the critical natural resource due north of our fair city.

Yes, the “our” refers to Northeast Ohio’s efforts to develop green technologies. But since the markets for these technologies (or rather, for the products produced that use these technologies) are global, not local, the “piling on” that interests me extends well beyond our own local VC community (which is still way too small for my tastes, and even theirs–see the report on the need for more early stage capital in our region at www.nortech.org)

And so you see I also agree with you completely about “the more pertinent question.” Lots is going on, but lots more needs to happen.