Check out the pumpabike (though beware of their retarded flash-only website design, I’d love to get the designer of this one out behind the woodshed). Another hydrafoil design, this one a trike concept where you hop up and down to propel the vehicle. It’s a lot more expensive (~$1,000 USD) than the last one I linked to but it also looks like a better, sturdier design. It’s worth dealing with their idiotic website design to check it out.