I've attached a picture of my HT speakers, of which I currently have six built and two more to go. They're quasi-line arrays using nine 3.5" full range drivers per speaker (these are the $8.00 closeout Aurasound copies that Parts Express was selling recently). The enclosures are basically a 5" CPVC pipe and the bases are solid walnut. Even though nine identical Aurasound type drivers are used, there is a frequency shaping network/xover also in each enclosure. The outer six drivers are rolled off to compensate for baffle step, and only the center driver handles HF info above about 5khz (which is accordingly boosted to match the lower frequency efficiency). So these speakers work more like vertically elongated point sources than conventional line arrays.
Due to the addition of activated charcoal in the enclosure and a "Vas reducing" polypropylene coupling capacitor at the input (600uF), my Audyssey MultEQ system measures these as responding down to 40-50 hz in my HT environment without any external EQ, no mean feat for an array of 3.5 inch drivers in a non-ported enclosure. And with the Audyssey EQ applied, it sounds like they make it down to near 20hz flat without any subwoofer in the system.
I suspect this approach has an inherent advantage over separate subwoofers because the bass for each channel originates at the same location as all the higher frequencies, hence there should be no imaging or delay problems caused by subwoofers that are located in only one or two places.
I've found that if I point the side channels at the walls, they effectively act as bipoles. MultEQ does a pretty good job of equalizing out the resulting response aberrations.
So, these speakers have exceeded my expectations for them. They can be placed almost anywhere without a stand, are not very obtrusive, work as either conventional direct radiators or bipoles, basically cover the whole 20 hz-20 Khz range when used with MultEQ, are very articulate and natural sounding and have decent dynamic range due to having 9 3 1/2 drivers per each with a healthy 4mm Xmax. Plus, I made them for a total material cost per speaker of about $150.00. Eventually I will get around to making perforated metal grilles to protect the speaker cones.