I ran across this alternative:
http://www.griotsgarage.com/catalog....topnav=FRHOL06 and it looks like it would work for segways! I'm not sure if it'd throw the balance off and cause the segway to wobble. But at least you could split the set between you and another segway owner to keep the costs low.
bystander, I'll split a set with you if you buy one!