There is an order in for more 4 cuft boxes along with the ported 4cuft box designed for some 12" woofers. As soon as those are done, the next thing will be the big 7.5 cuft box. It's still in the design phase simply because of shipping sizes. I do have one now it goes together just fine. I'm hoping to get it made for ported 15's (which should give a net volume around 6.5 cuft). And also use the same box for dual opposed 15's and 18's (which should give a net volume of 7cuft because there are no ports).
My time opens up pretty good in a couple weeks because most of my work has to be done by Mother's Day. After that, things should run much more smoothly from there on out.
Oh, and I'm trying to talk the CNC company into a short run of dual woofers in a vertical alignment and Jeff Bagby has been helping to design some passive radiator subwoofers in 10", 12", and 15" sizes. They're designed, just waiting for the CNC company to cut them.