The Lunar X-Prize site is featuring a design idea by the Selene team which really pushes on traditional thoughts about what landers might look like and how they work:
We are now pursuing a new lunar rover concept which involves deploying a rover that hovers above the lunar surface once the lander is secure on the lunar surface.
This new lunar rover uses a tether on a spool attached to a counterbalance. As the spool rotates, the cable unwinds in a measured and tightly controlled fashion ensuring a gradually increasing, spiral orbit for the rover around the lander as the rover attempts to travel the required 500m distance. Because centripetal force will vary based on the radius of the path travelled by the rover, the rotation speed of the spool must be constantly adjusted to hold the altitude of the rover steady.
This kind of thing really gets you thinking. Most excellent idea Selene team!