"[S]hipping luggage can be a cost-effective way to avoid punitive excess baggage charges, not just within Europe but between Europe and the United States , and indeed throughout the world. The solution is to use a baggage shipping service. For shipping to and from or within the United States, it makes sense to use a domestic company; but for shipping back to the United States, or between countries, you may benefit from a local company."
"[A] a travel trend has emerged to solve this problem: luggage shipping. Companies such as First Luggage, Luggage Free, Universal Express and Carry My Luggage offer door-to-door service without the hassle of lost, stolen, or damaged luggage, or having to drag bags along on your travels."
Both articles include links to various providers.