Have you looked at the "I've got shingles" thread by strthoky a little bit farther on in this forum. It isn't a download, but he gives a nice tutorial on how to make shingles very easy. I think he did it in "N" scale, but the same method would work in "HO". The other thing you could use if you want to simulate composition shingles is to cut strips from either "wet or dry" sandpaper or from fine sandpaper depending on whether you want tan or black shingles. Sorry, my mistake I just reread your post and noticed that you wanted wooden shingles. I think your best bet would be Campbell shingles. They come in a bulk pack as individual shingle made to peel and stick if I remember correctly. You should be able to get them at any model train shop.
