Thanks for all of your thoughts and suggestions... I think I've avoided a mistake.
Of course all these answers lead to more questions... Such as, are there other cabinet makers to look at that may have better bracing etc?
I'd like to come out of this with a strong sub - that performs amongst the best within reason and sanity.. . I had suggested $200 for the driver but there is some flexiblity on this cost. I'd like the whole project to run $700 to $800 (or close) with driver, cabinet, amp, and maybe something like the $100 sub EQ from Elemental designs if needed. I'm not opposed to one of the Behringer's for amplification or something similar so long as it is quiet without a fan running full tilt all the time. (amp doesn't need to be in sub cabinet).. The room it is going into is 14'x14' and is a dedicated theater.
Maybe I'm wanting too much for too little? In any case - I'm pretty sure I'm in the right place to find out. I've seen mention that DIY is the way to go for best performance, I just want to cheat a bit on the cabinet..
Bandit