I recently "published" a pattern for my Geese at the Cabin quilt in four different sizes. It isn't one that you can just add more blocks to as the Barn Raising aspect of it would be lost in adding more blocks. Neesie asked for directions on pressing seam allowances - another thing that is included in my pattern because it drives me nuts when I have to figure it out for myself. Pictures and/or drawings are a must. The idea of a pattern is to make it as easy as possible for others of all skill levels to follow. The more - the better! I think that having different sizes is very important and the fabric requirements for each size as well. I always give away a few patterns - so that I can ask for constructive criticism in return. I may be the first test sewer - but getting feedback from others is priceless. They can help you rate its difficulty also which some of us old-hands may have trouble determining.
Good luck in your venture - and know you are not alone in trying this idea out.