Thanks for asking, happy to share where I'm at:
I ended up buying a Wavecor SW182BD-04 from Mensiscus Audio when they were on sale as Meniscus was closing them out/going out of business.
I had my design narrowed to: The Wavecor driver in a 0.86 CF (net) box, with a 2" Precision Port, which would be tuned to about 27 hz at the full length.
Port noise was still a concern there... and a HPF would have helped a bit.
I was trying to fit the box under an end table, so I had very specific height and width requirements. I had been playing with Paul C's suggestion (for one of his Turtle/Burro/Pony designs) of using 3" PVC as a port possibility too.... but that got pretty tight with my size requirements. (I needed to fit about 12" tall and 9" wide, with front firing port and driver)
Attached is the Winisd design for that, with the (unadjustable) LPF that's in my amp in series with the LPF board I bought and would have added, AND a HPF for thumps, port noise, etc.
When you look into room effects, that can add quite a bit depending on size of the room, etc. So also a simulation of what that response might be like in my room attached. (At 17 watts into the 8 ohm driver, SPL @ 1.5M)
So, I got that far, had ordered parts to re-do the crossover and box on my S2000 speakers. Got set aside for a bit while I worked on some other projects this summer....and then this fall my wife changed her mind on our living room furniture setup. We have a little "bar" corner that she decided now will use the case of an old (1950s) TV we have to hold liquor bottles, etc. Very similar to this TV:
So that changed the scope of the sub project. If I have that (relatively) huge area under the screen hole where the speaker grille cloth is to work with, I could instead put the sub in that instead of under an end table. So that changes the available space I have to work with quite a bit. I haven't decided for sure on the exact design.... I'll likely use the 7" Wavecor as I already have it... (vs swapping to a larger driver now that I have more space.)
With the Wavecor driver in a 1.2 CF box, same filters, and a 3" port tuned for 26 hz, (no room response estimate added):
So until I get the TV box set up in the living room, this is on hold.
I did find that the Dayton driver that PC uses in the Pony seems to have a...unique response curve when I modeled it. More roll off on the low end, IIRC.
Let us know what you do!
-Nate