I missed out on a Metaframe style hexagonal tank that was up on eBay a while ago... damn. Swiped pic montage below:

Giving up, I decided I'd build my own, but out of scrap copper.

Link to 3D shot (cross your eyes to view).

The copper is sourced from 1/2" type "M" copper pipe and salvaged 16 oz roofing copper. The pipes were cut to length, annealed and then cut open to form strips abou 1-7/8" wide. I hammered all of the copper with the ball end of a 14oz ball peen hammer that I'd polished up. Afterwards, I cleaned up the edges. Whole strips were used for the top, bottom and strips split lengthwise for the upright tank frame parts. Joints were joined with either silver bearing plumbers solder (sweated joints), or brazed with brass rod. The light hood and legs are made from 16 oz roofing copper.

The light hood is sorta "turban" shaped instead of a simple and straight six sided pyramid, like the metaframe style hood. This meant each of the six triangular panels that make up the hood had curved sides instead of straight. The math to get the correct triangle height and arc radius on the side panels was fun... (I'm not going to show my work). Soldering it all together was a pain in the butt. The hood probably took me longer to build than the tank.

The glass is Home Depot sourced .125" panes (cheap) that I cut and then bedded in the tank with Dow Corning 795. Dow Corning 795 looks just like the tar/Gilsonite used on the old Metaframe tanks. Perfect for this project. It takes a long time to completely cure though, about two, sometimes three weeks, depending on the humidity.

I used SMD leds, 84 5630's mounted to an aluminum panel. That number of leds need about 24w, 2 amps at 12v. Thrift store power supplies are about a buck each.

I originally had planned on some cast zinc dragon fish for the aquarium legs. The molds picked up some moisture after burn-out (they sat around for a while) and the bottom half and fish heads have steam pocks. Also, they were too big and out of scale for the tank. Maybe on the next tank they'll get used. Or they may just get remelted.

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Updates:
This tank has been up and running for about seven months now.

Try #1-
At first I loaded it with a chunk of kiln dried grape vine and anubias. That didn't work so well. It looked great initially. I don't know if it was the vine (likely) or what, but the anubias slowly melted away to nothing, turning the tank into a hex shaped container of green muck.

Try #2-
This time I went with the old standby - 2" dirt substrate capped with old black EcoComplete. I planted vals on the back thrid and segregated them with a rock fence. In the foreground, I planted some pygmy water clover. It's some Marsilea sp., but not minutae, they're pretty tall (4").

The vals took off, and eventually the clover started to fill in. Snails and copopods were happy, so I added some nice nickel sized angelfish. Adios copopods. These angels have some wild mixed in, and are showing hints of a nice Dantum/cross shaped body and wildish coloration.

The angelfish are growing fast, and I think they'll be too big for the tank in another couple months. That means I need to finish the scrap copper cube tank that's been sitting (half finished) in the garage for the last couple months. This one will (probably) use the cast zinc dragon fish as feet, and be paned with low iron glass. I'd like it to be 360˚ viewable, so the bottom glass will have bulhead fittings and all filter lines will be from underneath. Maybe the power feed for the hood as well. We'll see.