I don't know how "elaborate" you want to get, but I saw in a magazine just today a man who designed his dog run as a garden! It's REALLY cool!!!! Let me go get the book....
Okay - I'm back! It's the April 2007 issue of Cottage Living. On page 55 there's an article titled Cottage Gardener. The article starts with the quote, "I start my day by seeing what's new in the garden".
The author and creator of the garden is Guillermo Castellanos of Evanston, Illinois and he has 2 border collies. Smaller than our children - but still a cool idea!
Actually, we took out two windows, bricked up the extra space and installed a french-style door from our office out onto a back patio area. It opens into the back of our house - and a large area we've fenced in (not the WHOLE yard which is REALLY big) just for the babies! It's got a covered area with an oversized house, concrete, a ceiling fan and water, plus all they have to do is go up the stone steps (it's how our land is) and they're in the grass of the back yard and part of the garden! There are plenty of trees, and it lets me "let them out" without having to actually walk outside with them every time they need out. It also allows me to let them play outside if I need to go away for long periods of time. They LOVE it!