They offered by far the best deal (the cost was about $250.00). The price included door to door service but since we live out in a small town I had to drop the parcel at the nearby fresno DHL place. THe bike arrived in less than 5 days. Parcel size is far more important than weight determining the cost. I made my own shipping box out of heavy duty cardboard reinforcing corners and mid section with 2x4 pieces. Try to make the box as small as possible removing all you can. If you have something to send with the bike that is related to cycling put it in the box.. you will not come close to the allowed weight.
I sent a single bike to Slovenia on Swissair Freight. It got there overnight, but sat in customs as the receiver didn't get the message that the bike had arrived. I think the cost was around $125, but I had to take the bike in the box to Kennedy Airport. I don't know what airlines fly in and out of Oregon, but I imagine anything flying to Zurich could handle it.
Have you called the freight divisions of the airlines? They can be found in the Yellow Pages (if Yellow Pages still exist). Don't go through the ticketing agents-you need to talk to the big brutes working on the loading docks. Also, check the Santana web site if you haven't already. They mention shipping tandems. Not sure the site will have all the info you need. You can also try calling Santana for advice as they ship a lot of bikes to Europe for their tours.