First commandment of MFK:
Thou Shalt Not Say A Tank Is Too Big, Regardless Of How Big It Is.
Second commandment of MFK:
Thou Shalt Try To Outdo Said "Big Tank" by Making Larger Tank, and Posting the Build In The "DIY" Section...
And really, "not attractive"? How do you aquascape a 50,000 gallon tank? There's like two options:
Sink a Boat in it
Put 5 or 6 HUGE rocks in it, with half a tree as Driftwood.