Mostly sewn together from the instructions available on the freescale community docs.
This doesn't distribute the freescale sources, download L2.6.35_1.1.0_130130_source.tar.gz from freescale. It is available under Linux -> Linux Source Code Files. Download requires one to make an account and login.
After downloading, place in this directory and run:
docker build -t imx28 .
One can change defconfig before build to their liking.