If so, any ideas how much a 1/2" thick-walled, 24"W x 48"L x 14"H acrylic tank would cost to have built? it’d also have to have a lid, I suppose 26"x50"
it’d have to hold water, so a cross brace across the top would also be likely
since we’ve every other sort of trade here, I’m assuming we’ve an acrylic worker 
just got done doing some measuring…
I’d like to have an aquarium built to house an African Lungfish. The tank would also double as a coffee table, so it is an odd shape. The Lungfish is a river fish, so the shape should accommodate it as well, too.
I’d like a tank that’s 20" tall by 56" long by 24" wide. One side would need a notch cut into it about 4" deep by 16" wide (I could get exact measurements at a later time) for a hang-on filter. Along the aquarium’s top rim, some sort of feet or spacers would be needed to support the lid and leave an air gap of about half an inch. This fish is an escape artist but would still need a huge amount of air exchange… The lid would be a sheet of acrylic or glass, whichever wouldn’t sag. The lid should also overhang each edge by about 4" to make it look more like a coffee table, there should also be an access panel somewhere in the lid about a foot square for water changes, feeding, service, re-arrangement, etc.
How much money am I looking at? On your site, there is a 70g wide that is a similar size, but it is glass and probably could not have the hang on filter notch cut into it, though I may be wrong, so I’m assuming this tank would have to be acrylic, even though I prefer glass aquariums.
As to cost: in a word COSTLY!
If I just had to have a plastic aquarium I would seriously consider polybutrate used as bullet proof barriers in some banks and check cashing facilities. It is highly resistan to scratches whereas methylmethacrylate scratches quite easily.
Call a local plastics supplier or check $$$ on the internet.
The joining of the corners is critical for strength. The greatest stress is around the bottom as the presssure there is due to the depth of water in the tank.
This is not something to be undertaken as a do-it-yourself project unless you have the prequisite skills and shop facilities.
There are custom builders who can build such an aquarium.
Side comment: Aquariums look much better at eye level or at least up off the floor where you can look in through the side. Looking down into the tank is not a very satisfactory viewing experience. Be sure that is what you want before embarking on this project.
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