Don't "build" a sump, if you have the room go to tractor supply and get a poly stock tank and us it as a sump. Easy, cheap, and great sized. 100g is only like $65.00, 150g is like $119.
I use two of them as sumps and they are awesome. The only reason not to use one would be if you need an in stand sump.
With a large tank you will be able to support everything much better if you build a basement or fish room sump.