Since no one makes a cylinder, it would be cost prohibitive to have just one cylinder made. It would be much less expensive to buy another gun that is cartridge specific. Would guess somewhere in the neighborhood of five hundred dollars. The ticket would be is to get a raw cylinder from Taurus and have a gun smith drill the chamfers for 45 acp. But don't think that Taurus would be willing to cough up a cylinder to play with. Doesn't hurt to ask though. Another option is to get a 44 Magnum cylinder and have it drilled out. And would bet that this would cost about three bills.
Robert