What if you did that idea with the two ponds with the stream in the middle but still give it that L-shape, This would make the stream a little more dynamic with a turn it. You'd get some really interest water currents and with some larger stones in there I think that could come out looking really nice!
by the way I know rhino really well too! I have to use it all the time to build digital models of the products I design.
I was also wondering, I was reading about this other forum that you have, how do I subscribe to it? I was also wondering when exactly would you be going there to build, I think it would be a lot of fun to come help but with school I would have to make sure the two didnt conflict.