Here is one - it is not round but you can set it up any way you would like. www.unitednotions.com/fp_flutterby.pdf
I saw a diamond tree skirt and that was round and it could give you an idea of how to arrange them if you wanted that look ;) Okay, technically it is probably more of a courthouse steps I think - but you can see how it is constructed and make it in to a real log cabin of course.