And, come to think of it, Widget's Grand Master Ones, which may have been precedent.
GT's diy: 1500AL sub, 1200fe, horn plus supertweeter.
Widget's GMO's: sub1500, TAD 1102, horn plus supertweeter
The point being a long midrange.
My take on all this is that the JBL big 4-way monitor has been done. Great as it was, and still is, GT strongly advised us against the 10" at
300-1200 during the Project May affair. "That won't work," he said.
It's a retrograde step, unless, as Ari suggests, your ten can cross lower.
The hyper-engineered 14-15 from 30 to mid-high hundreds, from the 2235 and the TADs to the 2216 are terrific, but as the above two systems and Widget's link all show, there may be a next step.
The complicating factor is the specialist driver that can go sealed from <100 to >800 (1200fe?) is AWOL; the ones I'm aware of need a port or dedicated equalizing electronics.