is this possible?

[120fowlr]

I am thinking of breaking my reef tank and just keep a FOWLR tank because I don't want to get rid of my fishes. I'm just getting sick taking care of the corals...
I really want a bigger tank for a fowlr so I can keep a trigger and other large tangs. The problem of getting a larger tank is that my floor probably would not be able to handle it. I currently only have a 24" cube.
I was thinking of maybe getting a long tank, but not very high. I was thinking of maybe a 72x18x12, which would make it at about ~70g. The large fishes can still swim the 6' length, but it's still only a 70g tank. Do you guys think this is possible? Would I encounter biological problems even with a big badarse skimmer?
this would be my fishlist:
-LM Blenny
-Blue tang
-Yellow Tang
-brown tang
-pair of clowns
-mandarin
-pseudochromis
I'm thinking of adding these fish:
-Pair of Crosshatch
-A big Puffer specie
-large tang specie
-Some butterfly fish (dunno which ones yet)

 

[tank a holic]

I dont know if you can get a tank that size w/o having it custom made
why wont your floor bear the weight? i have a 125 up stairs with no worries

 

[120fowlr]

I would custom make it for sure.
I've had a 120g before, hence my name.. but it was scary because whenever I walk by the tank would shake a little. That's why I got rid of that tank and have the current tank.

 

[small triggers]

have you thought of reinforcing the floor??? would make more sense in the long run. And i do believe you would have lots of problems with a 70g tank with all of those inhabitants. My suggestion would be to make sure this is against a load baring wall. Or why not just keep the little 24 and keep some smaller fish for a FO tank?