Clever chap! My worry about suspending a sub would be the reaction forces from the driver. You might get very poor transient response if the sub recoils like a real big gun on Master and Commander cannon shots!
I like the radial port (a lot) though it might be difficult to obtain the required area for tuning unless it becomes very narrow indeed. The tuning of the area to match the length have become variables of enclosure size and difference between the inside and outside diameters of the nested tubes. The software to easily design one is hopefully already going round and round in somebody's head. Pi x R1^2 - Pi - R2^2 x L .
The shell which forms the port's outer edge could help to isolate coloration from the tubular enclosure inside. Steve Callas should be designing LLTs around this idea to avoid those huge ports. We've lost enough small children and Newfoundland pups to his oversized port dimensions already.
I think you need a nice curve at the outer edges of a much larger and longer cone. Where the port begins and the enclosure ends could be a difficulty. Somebody should build a prototype immediately to prove the concept!
This concentric port idea should have been worthy of a patent or at least a registered design if it is really new.