Ok here is what we've got:
Pond:
OD of the pond is 76"x31"29". ID is 73"x28"x27.5". I'll have the shell of the pond, 1/2" ply wood on the inside, 1" styrofoam to insulate, and then the liner. The foam isn't needed, but I'd like it in just incase. It will keep the pond warm. It calculates to 243 gallons. There will be 1"x6" around the rim of the pond. I'll use 2 pumps, but 1 filter. The pump of choice is a Mag Drive 12.
Rack on top:
In the diagram, you can see the pond is black. On the outside corners of the pond, I'll have have a 2x4 that is 53" high. These will hold up the 6 20 gallon longs. The red in the diagram is 2 more supports to hold the 20g longs up. 2 in the front, and 2 in the back. These supports will rest on the strongest part of the pond walls.
The tanks:
The tanks, as I have mentioned, are 20 gallon longs. 6 of them. They'll all have 2 bulkhead fittings, one for return, and one to the filter. They'll all go to 1" pvc, where it will go into the filter. Since the whole pond/tank thing will be 70 inches, I'll use another Mag Drive 12. It will get the water to the 20 gallon longs. The pond and tanks will be on one filter, but there will be two pumps. That will pump 950 gallons, at 5', per hour to the 20 gallon long tanks.
The filter:
The filter will be a 40 gallon garbage can. It will be hidden behind everything. This isn't a 40 gallon w/d with 10 gallon bio. This is a 40 gallon wet/dry with 37 gallons bio media. I feel this will be more than enough. I'll also have mechanical filtration, and a plant filter. Plant filter will be a 20 gallon rubbermaid with fast growing, low light plants that are nitrate absorbing. This will all be in my room, so I sure hope it is quiet. The w/d will flow directly to the plant filter. The plant filter will have have flourite (sp).
Here's a drawing: