Medical Marijuana Card?

Is their any state that currently allows the use and purchase of Medical Marijuana from a cardholder from another state? I am just asking because many Medical Marijuana patients travel to different states and they should be allowed to access and use of there medicines. Just as if the patient was using Vicodin that was filled in their home state and traveled to another state, they would have no problem using their Vicodin as long as they have a valid prescription.

http://www.denverrelief.com/legal-faq.php
Q: Where can I legally take my medicine?

A: No patient shall: Engage in the medical use of marijuana in a way that endangers the health or well-being of any person; or engage in the medical use of marijuana in plain view of, or in a place open to, the general public. Law enforcement has informed the Medical Marijuana Registry of the following: Any place outside of the patient's home is considered public. "In plain view" also includes the patient's yard or garage if that patient can be seen using their medicine by neighbors.
17 marijuana medical states: http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881
go to the site to read I think each state has its own rules you would have to find out before you visit if its possible or not to get your meds
I think we have a ways to go before we can do that...(or a lot of things)...sorry..if you do find out otherwise I would love to hear it, I would like to move from washington
to a warmer climate area, but not if I cant keep and use my card with the same benefits I have here...