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?
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.
I believe Hsu has an offering that would meet your needs
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.
Wilson Audio is coming out with their new Watch Dog Sub in March, which is about the size of a small bar refrigerator that weighs 275lbs. I spoke to some friends that went to Ces2001 and they said it was amazing, for either music or movies. They claim that it is very similar to the XS, which is in a class by itself. The Watch Dog will cost about $10,000. I purchased the Wilson Cub II for my HT room and I have ordered the Watch Dog Sub. I will post when I have a chance to test it.