Yakima sells mounting kits for all sorts of vehicles. While anything that would hold their round tubes will work, the Yakima mounts are pretty high quality and very strong. They're not especially cheap, but probably a lot cheaper than the OEM bars from the dealer.
You should be able to find what you're looking for at a decent bicycle shop. They sell the bike mounts separately, so you won't pay extra for the tubes and mounts if you don't plan to carry bicycles up there.
I have extra Yakima set including bicycle holder and rims brackets for other cars if you are interersted. In good condition, althought it could use some cleaning after some storage under the tree. MB bracket as mentioned you can buy separatelly. The $120 I paid was like 7 years ago. Might be cheaper now?
I went this route so I could lock the cross bars and add the locking ski/snow board rack attachment. This pic just got pulled from Ebay and looks identical to what I have. They are obviosly much easier to find when you search for ML cross bars as opossed to MB wagon cross bars. I think I paid under $100 for used ones, and they are fully adjustable so they fit the rails perfectly.
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