This is great and you did a wonderful job with your ruler work. First time I used rulers I wasn't crazy about it either but with practice you become very proficient but it is time consuming. I still love the results and with ruler work you can branch out to other templates.
This patter can also be found in the book The Cats Meow by Janet Kime. Hers incorporates the baby cats as well. If you are a quilting cat lover this book is a must have IMHO. It has been around for decades.
http://www.amazon.com/Cats-Meow-Purr.../dp/1564770613