Have you thought about a river tank manifold? http://www.loaches.com/articles/rive...anifold-design
I like at least 1 HOB on my river tanks. For me it simulates water coming up over rocks (rapids). You can use HOB's and canisters with a river manifold, as well as a power head.
Have you tried calling a local counter top manufacturer or general contracter for what you're looking for? You may be able to get their scraps. Buy them a couple of brew's and they may even cut it for you.