It might be a little late to mail order them but try Seed Savers Exchange from Decorah. I like to get heirloom seeds/plants from them since they are dedicated to preserving genetic diversity. There are also some beans that are a salmon color as well. You might want to check with Holubs although that is up in Ames area.

As happyday says - I'm not convinced by the day length idea. I've certainly never seen it offered as a reason for pod failure. Runners set both before and after the longest day here. The main factor in when they will start to appears to be how early we can get them in the ground i.e. how early the temperature is high enough and the risk of frost low enough. Mine have been flowering for a couple of weeks now, before they even reach the top of their poles, and the embryo beans are setting. The first should be pickable in a week or so. Because we don't have hot summers they will then go on fruiting until frost. Here is a link that might be useful: Reasons for pod failure

One pole(climbing vine) beans that I lik best is "Hyasinth". It starts flowering and producing beans from June till November(right now). It flowers and grows beans non-stop, and attracts bees. What is more is that it has the most beautiful fragrant purple flowers and beans. The beans can be harvested young or left to mature. The color and cluster of the beans also are very pretty. It is perhaps better than some mail box flowers or morning glories(which do not have fruits and the flowers are closed most of the time). This past summer I had another pole beans (orange color), Cypress vine, morning glories, passiflora Incarnata, all climbing on the same arch. I have been most happy with Hyasinth beans than the rest combined. I will not plant Cypress vine next year, although I have so much seeds of it. The passiflora will grow back and I will just plant Hyasinth Pole beans and maybe two wild morning glories(non-lobed leaves), which are much pretier than cultivated ones and flowers grow as a bunch. Back to climbing beans: My all time favorite:Hyasinth.

Glad you mentioned the beans. I forgot I grew them on 14' bamboo when we were in Beaverton. Go to the top in about 4 weeks, then filled in. It was an eight pole TeePee of bamboo poles. When we get back to Washington County, that's one I plan to grow again. Nice plant for food and flower.