Mike congrats on finding that shark tank guy, i knew someone had posted it on AA but couldn't recall where it came from originally.
i got a chuckle out of the concrete conclusion myself, i just swore he used cinderblock for the bulk of the stand.. must have been a different tank.
now if you want to build the L shape tank (or similar) you are going to seriously need to reinforce the flooring, remember 1 us gallon = 8.93lbs, don't forget to calc in gravel, rocks/decorations, to get a good ballpark figure. if you follow the old addage of 1lb of gravel per 1gallon of water..
water - 8,037 lbs
gravel - 900 lbs
Rough total - 9,000 lbs ~ 4.5 tons
Thats not including the wieght of the tank, the stand, etc.
i would contact a struct. engineer for ideas on how to reinforce, but this will be huge investment, before you even add any water and not to mention any fish and if your going to use acrylic for the tank, its going to run you a moderate fortune.
it would probably be in your best interest to plan what you want to use for filtering, lighting, etc Now, then do a projected Monthly electrical bill after installation.