If you want a BCC that won't be 10' long then get a male. They generally average about 7-8 feet. Out of the BCC's I like the Peruvians most. But my favorite has to be the Argentine boa BCO, and there is also the Peruvian Longicauda BCL. True red tails (BCC) are normally the largest of the species. If you don't think you are ready for one that could easily hit 8-10 feet, then I would suggest starting out with a Central American, Mexican, or Insular Island BCI's. Here are the links to Gus Rentfro, Vin Russo, and Jeff Ronne's websites. They have alot of info and photos of a variety of boa constrictors...
http://www.riobravoreptiles.com/index_livestocksite.htm
http://www.cuttingedgeherp.com/contactinformation/
http://www.theboaphile.com/available.php