Doesn't the 1812 cost $30,000? I don't think I'd want half my budget going to a subwoofer....
Persoanlly I'd go with an RBH CinemaSITE (with 7 SI-6100 in walls) and a pair of SVS PBultar/2s. Then spend most of the rest on acoustic treatment....
Other suggestions: Get a HD-DVD player and a Blu*Ray. They'll look better than any upconverting DVD player. (when fed HDDVDs and BRDS respectively).
Buy the Outlaw pre-amp. You'll just have to upgrade your preamp in a year when HDMI 1.3 finally shows up (bringing Dolby TrueHd and DTS Master HD with it), and you might as well save some cash on the product you're just gonna replace anyway.
The Velodyne 1812 is around the 10k to 15k range depending on where you get it. DigitalCraze.com has it for $9,999.99. The Genelec has a similar price range but can be had for less.
I heard on AVS that the DD-18 pretty much matches the 1812 in output, so there's no reason to get the 1812 besides bragging rights. A pair (or 4) of DD-18's would be pretty sweet. With 4 you could really experiment with placement to get the flattest possible response throughout the whole listening area.
Art does have the quad SVS PB12-Plus/2s that I worked hard to get sounding like they now do, but these are now sharing space behind the screen with the subs:
btw, what happened to all of the tools and posting features in the "Reply To" window?
Art was a beta install for the internally powered (1kWx2) main speakers I have been working on. They are not small (but only 13" deep), and those are 12" woofers.