Mini-Micro Subwoofers?

Parts Express still has the other Tang Band 5.25" sub for under $20. I'm just bummed that they discontinued the 4" W4-992S driver. I bought a pair to use in a couple of tiny subwoofers for some ultra-small full-range speakers I have that use Tang Band W3-594S drivers in small sealed boxes, but nobody else will be able to build them unless they already bought some of the W4-992S during the clearance sale.

[IMGDEAD]http://web.ics.purdue.edu/~rbuszka/264-824_W4-992SD.jpg[/IMGDEAD]
 
Here's something a little more germane to the thread -- it's a sub I built almost a year and a half ago now that uses the W5-1138 driver. It's a "Decoupled Antiresonant Line" design ("Daline"), which is like a bass-reflex box, but tuned with a transmission line. Right now it's powered by a 75W plate amp, but I'm thinking of putting my old 150W plate amp on it. The amp itself is remotely located.

[IMGDEAD]http://web.ics.purdue.edu/~rbuszka/dalinesub.jpg[/IMGDEAD]
 
I think the daline design needs a little more fine-tuning, but it's extremely clean with that particular driver. I built the daline sub about the same time as I built my Wave-cannon knockoff, but the Daline sub turned out a whole lot better. The fine-tuning that I'm talking about is with the rear-chamber volume. I feel like it's not 'decoupled' enough, so the enclosure is just behaving like an acoustic labyrinth (second pipe resonances and up still pass out of the terminus, making crossover setup tricky). Still, its output is impressive for what it is -- it fills our whole open-plan house with full-throated bass to about 40 Hz, though it has trouble working into that massive room volume.