There is currnetly no way to extend the throttle sensor harness per Harley.It is made from some very special low resistance wire that cannot be soldered.You will need to wait for options.I are a Harley tech and it's a common complaint.Have you attempted adjusting the bars yet?
only option is tallboy bars which I think will make ya reach more.I added a backrest that seamed to help me.HD has VERY few accesseries for the 08 touring bike.I waitin for them to come out with the road zeppelin seat for the 08.