DB, I admire you for figuring it out yourself and not going with the crowd. There's hope in everything...you'll figure it out. I know you speak from experience.
FYI the high dollar glass filter sells for $490.
You think ray is the only messy fish? Get some koi and carp, feed them, and you'll find out those bottomless creature is as equally messy like ray, if not worse.
Kendragon you're right about the pond filter principals being better suited to some of these "aquariums", I'd love to see pics of the set up you're talking about with the mats.
Good input. I know you do a lot of work with customer ponds...any experience with parabolic screen filters? Looks like an interesting low-maintenance design for mechanical filtration (speaking large tanks/ponds here). Pricey though.