I might just stick with my internals, I just don't like having heaps of gear in the tank. I wanted them all the same but one's slightly smaller than the rest, I'll live.
Just thought this would be a cool concept, guess it's just not practical.
Given the sump idea some more thought, it could be good. 10mm drill bit only $7 off TM, but would I need 3x 10mm elbows then?