Al, The Sierra Click Pen has been around a while and you might get some opinions on it, but I think the click pencil has just come out (I just saw the ad from beartooth) so you may be hard pressed to find anyone that's done one yet.
Now I will say this. I have modified a standard Sierra to a twist pencil using a schmidt .5mm with good results. Maybe not the best solution, but much better than the clicks I've seen so far. One of the benefits is the tube length isn't changed. The Sierra click pencil that beartooth just advertised has a significantly shorter tube length. I actually want more wood on the final piece, not less, so I don't see me doing these.