One reson we don't hide all control mechanizms on .40 size and smaller planes is we need the leverage of the longer control horns.

While the pull-pull system doesn't need quite as large a control horn (pull is more positive than push) You'll still have an interresting time getting the lines rigged evenly. The smaller the control horns and the smaller the servo output arm, the larger a deflection a TINY mismatch in cable length will make. (and the less room for error in lining up the horns with the hinge-line)