As a former Dunlavy SCIVa user, I actually prefer the L707s to the Duns, and consider them to be something of a design tweak on Dunlavy's concepts. They are quite similar in presentation and feel, which is to say they are brutally honest. This can be disturbing: a client might think his mix sounds great, until played back on Duns or Lipinskis, then freak out and want to remix after pushing the warts forward. The Duns are the least flattering speakers I've ever used, but the L707s are a very close second.
The design tweak is separating the midrange and sub-bass sections of the cabinets. Dunlavy designs put each set of matched drivers in it's own sealed and isolated cabinet. Dunlavy SC-1AV's are essentially the tweeter/midrange drivers of an SC-IV in a separate cabinet (in fact, we had a set spec'd by Dunlavy as surrounds for our big stereo SCIVas, which became stereo subs in that configuration). Removing the LF drivers from the cabinets addresses my biggest gripes with the Duns: positioning them was ALWAYS a compromise. Rooms are acoustically lumpy by nature, yet the magic of Dunlavy's is fanatical attention to detail/parts to deliver near-ideal impulse response. The configuration of Duns retained impulse performance for all users, at the expense of potentially "lumpy" sound in different positions. The Lipinski design allows, or rather FORCES the acoustician to address both room modes AND impulse performance. When it's wrong it's ugly, but positioning is actually easier/better with the Lipinskis because sub-bass can be tweaked more.
Recently a couple different designers have been pushing stereo subs in opposing corners, rather than l/r. The idea is that this equalizes the pressure waves from both LF drivers in the middle/listening zone, while respecting whatever l/r positional cues may exist in the program. Such configurations are impossible with Duns or other standalone full range speaks. In a well-designed room, the benefits may be slim, but the closer your space is to commercial construction, the greater the potential the Lipinski approach has to improve your monitoring over full range speakers.
That's all I've got.
-d-