Ponoko does all kinds of materials. But the only two material types that are reasonably priced and applicable to keyboards are acrylic and bamboo.
Also, many people have good experiences with lasergist (their quality is great), but if something goes wrong, there customer service is horrendous. So much so that there is a good chance that whatever went wrong will never be put right.
Edit: I should provide full disclosure. Ponoko has been, but is not currently, a sponsor of meetups in Seattle. Was only sharing what they have because it was missing at the top.