Timothy;
i also prefer slender profiles on my carbines. From an accuracy standpoint, i cant tell much difference, except maybe the heavy ones hold a bit steadier for me when shooting off the bench...the early production carbine barrels were fairly slender, tapered barrels, 21" in length. New production are mostly 23" Bull barrels. To me, the tapered profile makes for a more balanced gun.
Try Ed's contenders for a fairly steady source of used carbine barrels, he is a sponsor of this site, but call instead of emailing. You'll get faster results. Ed also places regular orders from the TC Custom shop, where you can get tapered profile barrels made up in whatever caliber/finish/length you want, provided its safe to shoot in a Contender. As mentioned, Bullberry also does great work.