I have never ordered custom fortune cookies myself, but two of my coworkers did get them for their weddings. The first ordered from
http://www.fancyfortunecookies.com/ and the other from
http://www.exclusivelyweddings.com. Both had good experiences and got their cookies timely and as ordered, other than a few broken cookies (which is expected, I suppose, and mentioned in a review on the second site).
I attended both weddings, but I don't remember either cookie being particularly good or bad, just an average fortune cookie with more color in a fancy package.