Another proponent of radical yet feasible solutions for facing the oncoming decline in oil production rates is James Howard Kunstler, author of "The Long Emergency".
His page is http://www.kunstler.com/ and his blog http://jameshowardkunstler.typepad.com/ .
In fact, because of his personal style and his being a Democrat - though vocally critical of the inability of his party's leaders to grasp the dynamics of key physical realities - Kunstler may cater to a public that may not find Simmons much to their liking, out of his big business style and his being a well-known Republican (and advisor to Mitt Romney, who is not my preferred candidate - Ron Paul is).
It should be noted, however, that their views on how to deal with the Peak Oil challenge are not really conflicting with each other, as can be seen from a joint interview of both which took place on November 1, 2005, whose transcript is at http://www.energybulletin.net/19686.html . Worth reading if you have time.