Type in "library ladder" in the products section of Houzz and you'll see some options. This one is listed at $414:

Hello, Nancy,

We have priced custom library ladders in the past and $2,500.00 is not out of the ballpark. If it is actually a custom built unit (what we, as custom woodworkers, would do), there are kits available that consist of the hardware for the ladder. These can be around $700.00 dollars. Then you will need the rails upon which the ladder will run. They can cost a few more hundreds of dollars. Now you have to make the wooden parts of the ladder, assemble it, apply a finish, and install it. Unfortunately, I am unfamiliar with the "quiet guide ladder". One of our customers opted for a nice wooden stepladder rather than the rolling library ladder.

Good luck with your project,

Jim

If you are in the Minneapolis area, there is currently one on Craigslist - search "library ladder"