Probably some mail-order in the PNW.

www.ediblelandscaping.com

Have you ever eaten any of these? Several years ago I planted 4 vines. When they eventually produced grapes, I was very disappointed with the unsweet fruit. After the 2nd year of unsweet fruit, they were pulled out of the ground. Because I don't bother spraying, fruit also got fungus. Good quality muscadines are a whole lot better for me than are the 4 Mort. that I invested $ and several years' time in. I wish that I would have known before.....You now do.

Contact Urban Harvest:

http://www.urbanharvest.org/events/fruittreesalevarieties/grapesbunch.html

Here is a link that might be useful: Urban Harvest - Mortensen Bunch Grapes