What you are talking about is not really a "bellcrank", but rather a tiller bar. I have used Sig heavy duty tiller bars for years in large (1/4 up) models and have never had a problem. To see a breakdown of the tiller bar go here:

http://www.sigmfg.com/cgi-bin/dpsmar...nuF.html?E+Sig

You have to click on catalog at the top left, then on hardware at top right, then hardware again on the middle left. The heavy duty tiller bar is the first item listed.

Hope this helps some. I am going to start using the Kevlar cable in all my large models. It is NOT wire and will not cause interference with your radio gear like the wire cables will.

Take care, stay safe, and happy flying!