I don't think that most muffler shops would fab up any kinda drag pipe accept a straight through pipe. you might as well just go buy the correct diameter length of pipe from an auto parts store maybe 20$. The BCB I don't think is a bad deal it's got baffles in it and it comes with the gasket and wrap if you wanted to wrap your exhaust. So a straight through drag pipe would probably cost you about 45$ with wrap and to do baffles you'd have to custom build one. Otherwise your going to sound like an evil lawnmower going down the street.
here's a no baffle ebay drag pipe for 35$ shipped..
http://cgi.ebay.com/ebaymotors/SUZUKI-BOULEVARD-S40-CUSTOM-MUFFLER-DRAG-PIPE-...if you have a welder or someone with a welder who is willing to put a couple of baffles in your straight pipe that works too, but like I said that's not something I think muffler shops usually do. I could probably do it for ya for 75 if ya can't find anyone around you to do it.
you can also build your own glass pack muffler, but if you want it to look like a drag pipe it'd probably be pretty restrictive. (1 3/4 dia outside pipe with an inside pipe multiple drill holes in about 1 dia and fiberglass and steel wool in the space between the pipes to absorb some sound.)