There's another vendor who they talk about over on FG, but I don't remeber the name right now. I've had really good luck with MPI extensions and they run all the way up to 20g. wire and all of them with gold plated connectors. They are quite reasonable compared to say Futaba or JR branded as well as being bigger wire than those two both of which have 22g. wire in their HD servo leads.
http://www.maxxprod.com/mpi/mpi-3.html