You can design almost anything with zazzle. I've been using them for years; they send me coupons for my birthday and anniversary of my first purchase. :D Some of their products are top quality (wall decals, puzzles, shirts), others not so much (chocolate ended up melted half the time, but it looks like they discontinued that particular product), but their customer satisfaction policy is awesome. If you don't love it, you can get a refund or replacement--not many customization companies will do that. (Also, look at the reviews on each product and you'll get a fair idea of that product's quality.)
I've been using this site for gifts for all my family for years now. Customizing each item makes for great gifts. :) The fact you can also sell your designs (if you want to) through them, is another unexpected perk.