It's not quite full range nor a tower, but Ascend's new LX for $1398/pr (temporary pre-order price, they will be going up after this first batch, iirc) does dig very deep for a bookshelf with -3 dB of 36 hz. High power handling too ~350 watts. I think it's also the first speaker on the market to be fully NFS optimized using a Klippel, and scores very high on the Harman speaker rating. The measurements alone are pretty astounding and this looks like an amazing, extremely accurate, unique speaker.
These links should take you straight to the correct posts:
Measurements.
Specs
Pre-order link.