DIY cratch cards

[heathercooze.livejournal.com]

for a project I want to be able to make my own kind of scratch cards, like the kind for lottery tickets. I know of a method that is closer to scratch art (colour with crayons and cover with tempera paint then scratch away to reveal colour). But I'm more interested in being able to print (say, from my computer) onto a special paper that can then be scratched away at (the whole sheet, or just part of the sheet). Any idea how I can DIY, or possible get help from a company or resource that does this kind of thing? TIA

along the same lines... check this out