Any tube subwoofers out there?

The NOLA Thunderbolt sub uses an A/B amplifier. I haven't heard it, but it's received excellent reviews from both reviewers and users. It's not tubed, but is considered more of an audiophile subwoofer than most.

You don't see any tube subs because it is such a bad idea. Tubes can't control bass very well, tubes can't drive low impedences well and there is a loss of bass when you go through a mile of output transformer wire. And there would be lots of microphonics from the tubes shaking.

Why not buy a good passive sub and power it with a tube monoblock or single channel of a stereo tube amp?

You can use bass guitar amp instead.

I appreciate the response of Rwwear because that appears to be a reasonable answer as to why not. Some of the answers as to how it might be achieved intrique me and are worth considereing. .
My listening is much more geared towards the higher frequencies than bass in general, strings, flutes, piano, yes it can do bass as well as can cellos or basses. More bass is just not an adictive route for me clearer highs are. More depth is also appreciated. More responses would be as well.