I'm guessing complete custom driver designs exclusively for Danny. From their webpage:
HPV Technologies is a Solutions-Based company that can help your design team. To help you in finding a solution our Applications Group provides a no-charge design service to help identify which MAD System might be right for your application. And if we don't have an existing system that fits your needs...then we can design one for you!
Which leads back to my question. According to what I saw on their webpage, their standard driver is 6" wide x 9" tall.
With these dimensions, even if the drivers were direct sonic replacements for the Neo3's (which I doubt) they would not physically fit the Neo3's 4.3" diameter opening in the N and OB series speakers nor would they fit in the Wedgie.
On a selfish note, I'm wondering if I need to hang on to some of the Neo3 PDR's I have as backups in case my Wedgies or N3TL's have driver problems down the road