The serpentine setups were offered on BBC engines. They are pretty hard to come by, though. Be sure to install the reverse rotation water water pump as well, since the water pump is run by the back side of the belt in the serpentine set up.
Kwik performance offers a kit to adapt the sbc set up to the bbc:
http://www.kwikperf.com/bbc_serp_kit.html
as well as a stand alone set up:
http://www.kwikperf.com/bbc_m4.html