I would recommend trying any of the:

Youjiro

Yaguruma
http://davesgarden.com/guides/pf/go/57867/

Maisugata
http://davesgarden.com/guides/pf/go/106236/

Ipomoea tricolor is also a good choice for good coverage and the seeds will not survive cold winters...

Hope that helps...

Ron

P.S. - Many merchants offer incorrectly identified seeds,so be sure to obtain your seeds from a source that has correctly identified seeds...

Here is a link that might be useful: Ipomoea tricolor in the PlantFiles

really fast growing and absolutely gorgeous is "scarlet runner bean" - actually edible beans, but never tried to actually cook them... you can find them at Lowes in the seed section, if you get there early - just look everywhere you see seed pkgs. They're especially nice because its a one time thing - totally non invasive. If you like them, save the bean pods and use them as seeds next year