This is what I did:
I really hope she likes it. It is, in fact, 3" across, and it seems awfully light for its size. That's one of the advantages of polymer clay. I basically made an original, sculpted and appliqued with clay on a circular base, then took a mold and made this one for her. If it works and she likes it, I'll be making more to supply to the shop so that people who buy her pattern can also buy a button to go on the finished product. I'm excited!
I think it's really cool!!!
Also, I'm taking 11 new button sets to Tempe Yarn and Fiber today, including some shown below. The pinkish/fuschia and the peach ladybug ones are absolutely one of a kind. They were leftover colors from another project and I can't mix them again, so get them while you can if you like them.