Hi Bell, as Tote has posted , the Dolium rails as used on the WindCheetah racks may fit. I suggest you investigate before going down that path. I can advise that the Rhino rails are a no go. They are the wrong shape to fit the underside of the Expedition rack, and and simply too low. I learnt the hard way, and now have a pair for sale.
The Expedition rails from LR are pricey, but at least you know they will fit.
Note - If you are buying an Expedition rack from LR, they will normally quote with the rails. Again worth checking before you proceed. Not much point ending up with two sets of rails.

