You probably aren't going to find plans for something on the small side anyways. Just gleen details from the photos what you like/can accomplish. Go to that member's BYC page and see if there are any step by step photographs. Most coops seem to follow a basic form and then options can be how you roof it, how the doors look, the siding you use.... those are the easy things.
Have you checked the coop page on this site? So many nice ideas there.
Some members might be willing to help you put together a materials list based on experience building their own coop. But basically, they're all squares/triangles.
PS - a rabbit hutch works fine as long as it's strong enough and the proper wire is used. This will be the same regardless of the design you choose.
Good luck!