Casio I know of a number of VS firms who focus in cleantech, and this is an area set to grow immensely both within mainstream consulting (wrapped up in a broader 'sustainability' proposition) and within VC/PE as they seek to move away from the diminishing returns (and high entry costs) of traditional markets. Your combination of cleantech, a good grounding in a decent MC firm, and transactions experience would will be compelling in a few years. On the transactions side, try to get experience throughout, not just on executions and due diligence - this is the meal ticket if you want the VC exit option. Someone with your experience won't be expected to have origination experience, but if you know how to put a blue book together, you suddenly become a hire they can put straight into the fray.