tall front firing Sub for audio?


hello everybody,
looking for a front firing sub that will approach the height of my main speakers (@4'); heard that this approach will greatly widen / heighten the soundstage (as opposed to a shorter sub). mfg's/models that come to mind are Wilson PowWhow and VonSchweikert's Tower of Power. anything else out there that's great for audio only?
alternatively, anyone ever stand mount a sub? what happened?
128x128rhyno
latest issue of Listener, Dr. Harvey "Gizmo" Rosenberg has stand-mounted Carver subs to good effect in his article on "Fourth Modal Wave Loudspeakers". Gizmo has Tannoy Westminster mains, which stand 5 feet tall and weigh 350 lbs. each in stock form.
the wilson whow is actually a down-firing sub. wilson does make a floor-standing upright sub, the xs. it is, however, 84" tall. and quite pricy.