I managed fairly easily to get 13" of rear wheel travel out of a single pivot bike with 17" seatstays and that was with a 2.5" tyre.
223 with a longer shock in the slackest setting? fits quite well with my argument, the swingarm is loooooonnng to flatten out the axel path and avoid the seat-tube.
It's vertical position (well above the chainline) is the point at which the wheel starts to move forewards (so below this point it is moving backwards to stop pedal bob), so in fact the 5's swingarm actualy has a foreward axel path, hence travel is limited by a combination of chainstay length and tire/wheel size.
Did you see the MOJO prototype/one-off ornages at fort bill a few years ago, S-shaped DT to get the pivot lower, but with a long swingarm to flatten out the axel path. Essentialy a 223's pedaling performance with a better axel path.
As for braking performance of maestro, i never said it was bad, just that spesh bikes i've tried were better (IMO).