Eco-friendly Wetsuits

Are there any wetsuits for open water swimming made from Yulex (a patented type of rubber) or other non-petroleum-based materials? I've seen lots of Yulex suits for surfing, and would rather not buy Neoprene (unless Neoprene isn't as terrible as I am lead to believe). I'm considering getting a sleeveless Patagonia suit, on the assumption that I need the mobility in my arms, while my legs can "surf" along behind. Thanks for your advice!