We have used other telescoping tillers (Alcort) and they work well. We have not come across a tiller longer than 8′, for that requirement we’d start to look at continuous line steering like some sailing canoes use. There’s no reason you couldn’t have both.

Hello Ben,
I am not sure I quite understand your question. I want the actual tiller to be adjustable in length, and ideally in an easy and efficient one-handed operation. The only system I can think of would be a kind of twist-lock with inner and outer elliptical or oval tubes. My current tiller is about 8′ long and that forces me pretty much to sit at the aft end of the cockpit. I usually sail single-handed and I think it might help to be able to move further forward especially when going up-wind. I could of course make a longer tiller, but that would be in the way when tacking. I can think also of several ways to make an extendable tiller that would require two hands for adjustment, but I am not interested in that. I would be prepared to buy an extension like the Ronstan Battlestick, but they seem to have only a max length of 8′.
Thank you,
Viktor

Do you need the push-pull tiller that comes off the cross piece or an extension for the push-pull tiller?