There was a run of projects for a bit and a search for CANVAS should pop them out. @shogun had some really amazing results and his post got me looking at pre-painting resources.
I started on some canvas I had laying about but soon just moved to draftboard (because I have a metric ton of it - shrug).
Here is a Turing puzzle I made on MDF, using blue paint covered with a tan color paint. Those colors seem to pop with flesh tone pictures.