I think you should hold on to it! You have the Domain of Domains if they get huge. You hold the original Hybrid Cab .com . No stop words or fillers. I think someone will come to you once the market for hybrid cabs opens up. You will get a call from someone in NYC, maybe a manufacturer, or dealer. Maybe even the city. A true GEM! Not as huge as Diamond .com, but truely an original domain. I would say if hybrid cabs take off, you are holding $xx,xxx possibly.