There are a bunch of cork board samples in the gallery.
Gallery at Splitcoaststampers
I did a 6x6 cork board at a stamp camp a long time ago. Everyone had a blast and they came out nice. We used Craft inks. You could also use the new Petal point chalk inks. The cork does absorb a lot of the ink so use brighter and darker colors. Also it's better to use solid stamps. Outline stamps don't work too well.
Have a great day. Hugs and smiles.