Here is a link to a thread started by Angie1123 showing some of the details of her 125g in wall tank her husband put together for her. Just be sure to take into consideration the shear amount of weight you will be dealing with when you build the support structure... 180g at roughly 8lbs per gallon, 3-400 lbs of glass, plus your LR equals a LOT of weight.

Overbuilding the support stand and stuff may increase the costs a bit, but will let you rest a bit easier.