The Largest Commercial Cylindrical Slide Rule Has a Scale Length of 24m

That depends on what you mean by "how much it would cost to make." As far as materials go, if you wanted a period correct replica, while you probably can't get actual Bakelite (I'd go with brass, if making it look exactly like the model isn't a big requirement), the rest of the materials are probably easy and cheap to get. As a one off, your main cost would be time, and the necessity of being able to access a decent shop. Using more modern and durable materials would probably cost more than using basic materials from 100 years ago, I would guess.

Probably the main constraint is the ability to make precise markings on the cylinder. I bet you could do that with a fairly simple CNC setup, but it would probably require some custom programming. All in all, it seems like a well-equipped personal shop or maker space should have all the tools necessary to do it. For a single piece, it seems like it's just a matter of time and ingenuity in developing the manufacturing process. Scaling up production is an entirely different matter, and who knows what the costs would be at any significant scale?