I don't remember where I first saw this many years ago, (maybe in Dean Pappas' column in Flying Models?) but I've used it several times in pattern planes. It has zero slop and is very precise.

The pushrod is a hollow rod, like an arrowshaft or CF tube. There is a threaded rod (a long 4-40 screw works well) that passes through it near the rear of the fuse, and exits just clear of either side through slots in the fuse that are long enough to allow full travel of the pushrod. The rod ends get those milky white nylon aileron horns screwed onto them, and then two short regular steel pushrods to the elevator horns. The front of the pushrods get solder clevises for attachment to the aileron horns.

The end of the hollow pushrod rides on a wood dowel glued into the tailpost (shown in red), which is long enough to engage and support the rod during it's full stroke. The dowel needs to be a relatively loose fit so the slight lateral displacement the pushrod will have from servo rotation won't make it bind on the dowel.

Here's a very crude drawing to help illustrate. Drawn looking from the top/bottom:

Rick