Probably the most "Beta" hero I've ever written is Shane Graham in my western historical, Abducted at the Altar. In fact, the original story had been rejected because he was too "beta", too willing to help the heroine. I sat on that story for a while, but loved it so much, that I reworked his character a little and was able to sell it to my publisher. He's a great hero, strong when he needed to be strong, a true reluctant caring man-next-door type for my feisty heroine, Dorie McCabe.
Another great example of Beta Man is the hero, Danny Tucker in Erin McCarthy's book, Heiress for Hire. It's a story that has stayed with me for a long time and recently became a 2007 Rita nominee.
A Beta Man is often: