I used the E'Wave crossover modified slightly for the Advent woofer, and that worked fine for starters. I'll get back on that and finalize them in my Advent thread.
Jackgiff has a pair of these waveguides, and you'll likely soon see documentation of what he's doing with them in the E'Wave thread. We're both using Selenium drivers.
Skywave-rider also has a pair, I believe. I haven't heard what he's cookin' up yet. Maybe he's waiting for me and Jack to get our respective acts together.
This economy version of the 8" square PT-D95HF-1 PT Waveguide shown costs $14 apiece. The Part# is 364700-001. Order from JBL Pro Parts with credit card at (818) 894-8850.
Here are the new JBL products that use them:
http://www2.jblpro.com/catalog/General/Product.aspx?PId=232&MId=2
http://www2.jblpro.com/catalog/General/Product.aspx?PId=234&MId=2