There is a way to hand pollinate beans, though I have not done it. However, here's a link to a book that does give the technique.

This year I attempted a cross with beans. But my approach was more low tech. I simply planted the two kinds on the same pole and will re-sow the resulting seed. I hope to get a cross this way.

George
Tahlequah, OK

Here is a link that might be useful: Carol Deppe's Book on breeding garden varieties