I just ordered one of these today on eBay. $16 free shipping.
These look to be custom made which means someone is making and selling the special 2.5mm locking connectors. I sent the seller an email asking to get more details on the type of wire used and where I can buy the connectors. I'll update the thread once the order arrives.
Edited by OWiseOne - 8/2/13 at 5:16pm