There is a Desert Nine Patch in the Keepsake quilting catalog that shows a closeup of the quilting in the neutral blocks. It is a sun pattern that might work for the circles. It is used for a block, but could easily be adapted. It is a circle in the middle and rays extending out from the middle. The catalog I have is the Spring 2010, but the kit has been in several catalog. Hope this helps. I've been dying to try it.
Susasn