They are all over now. You can even have it done online if you send the file, but I understand it can be a bit pricey. If the library doesn't have one, you might check around in town for someone who does it for a reasonable price.
The blocks are pretty simple and don't require anything special to produce. And, they don't need a lot of filament either.
I found a guy locally who has a company that can print these for a decent price.. now I need to figure out how to install these. Is it possible to raise the top higher than the bottom to install them? I will do some more research.
There's a thread in the reference section that discusses their installation. You do it with the top up as I recall and you take the guide rails off, probably all around, to give you more room. Then, you'll be able to pull the top toward you to open the space behind. I'm sure you have to use a small right angled screwdriver. I suspect it will be a bit "filddly".