NASA's "Big Wheel" rover ought to do quite well on Titan. Probably not possible to do a high-fidelity test here on Earth, but if there are wide enough margins in the concept, that shouldn't really matter.

I agree, however, that a helicopter would probably be the better way to go. You're probably already familiar with the design for this</a? link is to a PDF file It looks to me like the main potential limiting factor would be its on-board intelligence: a rover has the option of simply becoming inert in an unknown dynamic environment; a helicopter doesn't. If an intelligent enough autonomous piloting program can be developed, however, I don't see what else would stop us (aside from money, politics, bureaucracy, et cetera) from sending a helicopter out there in not too many years. Cheers, Nathan.