Well, as with most things, timing is everything...
I appreciate the info around the Fostex, perhaps I was mistaken, but I thought that they were releasing new versions, which as JLM alludes to, were far more expensive.
I ended up buying a set of the CSS 4.5 inch full range drivers, but they are far from being rated at 30-20K - no matter to me, since I am happy with the sound they are producing, in the box I have cobbled up.
Glad that JLM is happy with his build, and hopefully you will be pleased with what you come up with, using the Fostex drivers.