river tank

Hi folks!
I am sure some of you have seen the "River Tank" system that is for sale.
Its the one that comes with plastic rock-like tank dividers and background
parts that you glue together in side the tank to form little waterfalls and
pools. I like the idea but the fake plastics rocks are really ugly. Has
anyone ever built one from scratch so to speak, using real rocks ? Can
anyone offer me some advice on how to go about doing this?

xero at localnet_com