Our letter stamps are, to put it precisely, kickass! They are the easiest to use, easiest to clean, easiest to keep organized, neatest as far as the inky fingers factor, and our fonts are great. Here is our new one, which will be coming out in January: Typewriter typeface, which was designed by Chank, the famous hipster font designer (who happens to be local and a friend of mine).
We're thinking of using this font for a kids' t-shirt stamping kit; here's a couple I made up this morning. Dang, I gotta make one of those "chicken butt" ones for myself!