Mike,

MK products makes a ball bearing dual elevator setup just like described above. As for the Y pushrod setup. I have done that many times w/Dave Brown pushrods. The think you have to remember is that the elevator servo output must be in the exact center of the plane to get the Y pushrod to push/pull evenly on both sides of the plane. If you do not have the output in the center, you end up with "differential" elevator which is always good for a solid 5 for inside/outside loops since they will look like a corkscrew. I still use Y pushrods with the servo output exactly centerline and have no problems with loop trimming.

Dan