It was some time ago and I can't recall the name of it. It was around San Francisco if memory serves. What was so striking about the garden was that the owner had trained apple trees and other
fruit onto trellises, or rather they were espalier. Don't know if it was a special type of tree
but seemed both beautiful and very practical. In your case it will benefit from any rain that comes off the roof (just redirect the downspout or use rainbarrel to collect it then add drip hose attachment to it), though it might help to lay a drip or sweat hose down along the base of whatever you plant.
This estate also had the most beautiful olive trees (not espalier). I so wish I could grow them here.
Anyway, here are some websites on espalier fruit trees. Unlike most veggies whose vines are temporary and must be cut back after harvest, these would be permanent. I don't know how compatible this would be as far as sharing space with grapes, however. Grapes could easily cover that whole wall as I believe they are prolific and aggressive.
Anyway, sounds like a fun project. Best of luck!
The Fine Art of Espalier Pt. 1 (parts II and III found in index on left side of page)
http://www.frenchgardening.com/tech.html?pid=312615870324755http://www.backwoodshome.com/articles2/hooker79.htmlhttp://www.ehow.com/how_14669_espalier-tree.htmlhttp://www.henryleuthardtnurseries.com/