To ellaborate a little bit, when i was shoping for a high excursion driver I learned that the RE XXX is pretty much the only sub out there with more than 40mm-ish Xmech other than those prototypes that pop up. The standard 1/2 roll surround allows for 3.25"-3.5" p-p excursion. So all Fi, AA, and same surrounded drivers have the same Xmech or less. The LMS ULTRA, SS XXX, RL-p, and other tall narrow surrounds have about the same excursion capability.
What I kind of knew and what was reinfoced was if I can make a giant box for my cheap IB3s that have the same max excursion capability, why spend more $$$ to save space getting the same displacement. I shopped and shopped for a surround that would allow further travel because Scott said if I can get it, he will build it. He said Xmax is easy.
That sub is a 10" so it LOOKS like it moves more, but thats because the 11.25" ferrite slug was too big to allow making a 10" BTL.
Scott is working on surroundless drivers and a tech that helps with "blow by". Thats all the detail he was willing to give me.
So to my knowledge there arent any "high excursion" subs to be released from Fi, nor any new IB subs as per the email I posted.
RE Audio XXX is IT, wish I had some. Ricci has stated anything past 3.5" starts to dimple, even the XXX, so I don't see excursion potential changing any time soon unless this surroundless driver comes out.