If you are set on cleantech, the best places are McCombs and Haas. I work for a cleantech firm and that's where most of our post-MBA's are from (with a few more from H/S/W). Both are great but given the choice I'd probably go with Haas if cleantech is the goal.
However, when a cleantech firm is looking to hire someone these days, there a half dozen qualified candidates with prior cleantech experience given all the consolidation in the industry lately. You will be a lot more successful going for a more traditional energy sector role first, then transitioning to cleantech. Worked for me.
Hey, if you're still around could you explain what role you transitioned from and what role you transitioned into within cleantech. Energy is my passion, and I've been working in oilfield technology for 4 years. I had the chance to jump into solar at SolarCity but the job didn't look very challenging from a technical standpoint and it didn't seem like I would learn too much about the business side or the development side from it, so I passed. It is still sort of a dream to somehow work in this area - though I'm not sure what an MBA can do when the tech itself is not that mature.