I know what your saying, but i dont think its possible, the cable slide moves an awefullot on the guard. Plus it would get in the way of the arrow cause your cable guard is right about the same height as the nocking point.

I think what you may have seen on the drury could be a type of cable guard silencer that sticks on the end of the guard.

Here is a link to a review i did of the sts. http://www.huntonly.com/2006/09/sts_shock_terminator_suppresso.html

I know you dont want the front mount style, but i have one on and dont think its to much extra. I just dont think its possible to get one that would mount on the end of the guard w/o interfering w/ the arrow. Unless it was far enough offset, which would be more cumbersome than the current sts.

Also another thing to think about is that the cable guard is not designed to take that impact, most are made outta carbon fiber and would crack or even shatter after enough shots...