In the US, DHL now offers shipping of box sizes above the previous limits of Fedex and UPS. This is "Oversize 3" and allows 160" of length plus girth ((2X(W+H)) and they charge you for 90 pound of weight.
So it now easy to ship a tandem for about $60 half way across the country!
Thanks to those with advice on my recent tandem deal. Also Champaign Cycles in Champaign, Illinois did a great job of packing the bike and coordinating the shipping. Great attitude about what I think of as a PITA job.
Joe Bender-Zanoni
Great Notch, NJ