For my guinea pigs I made a cubes and coloplast cage. You can make it what size you want - and a double height of cubes should keep a bunny in, or you can make a lid aswell.

Here is a link to the site for how to make the cages:

www.cavycages.com

Glad to hear she is coming in, my Mum didn't want the guinea pigs inside at first, when they came in she loved it and they did too.