Just to follow up here.
It turns out that the shipping charges for the SDX15 were not as cheap as I thought. $80 just for the driver is a little steep for me. The amp would be another $50 or so.
Luckily, Kevin Haskins from DIYCable offered up $43 shipping for the Exodus Tempest X2 (15 incher) and I got an OAudio BASH 500 coming for just $19 shipped.
So, the plan now is to make a sealed 6^ft (net after stuffing) enclosure with a Q of .675 for the Tempest and let the low end boost features of the OAudio amp get me to a 32hz F3. I should be 7db's down at 20hz. Hopefully my room gain can make up for the dropoff and get me closer to flat through 20hz.
May just be my imagination,but I've always liked sealed subs better, but if this design doesn't work out, I have a ported design as backup.
Got all the mdf cut and am starting to put the box together. The driver should be in this week, and the backordered amp should be here in two weeks.