John,

You can get these tiller extensions from any Ronstan distributor. They are called Battlestick's. You can also claw your way through the vast product catalog at Annapolis Performance Sailing or Murrays Marine for a whole range of possible solutions to suit your needs.

http://www.murrays.com/mm5/merchant.mvc?Screen=CTGY&Category_Code=C-H&Store_Code=MS

Some of these sticks have the bendable, quick-release foot and others are hard mounted. They can also be had in various telescoping lengths, depending on how you want your boat setup.