[abc3]

Do you know which libraries are doing this?

[makmanalp]

Cambridge public library does it: http://www.cambridgema.gov/cpl.aspx

edit: not the digitizing part, just the artificially-scarce ebook loan.

[abc3]

Do you mean the Mass eBook project described here: https://www.cambridgema.gov/cpl/eLibrary.aspx

Or is this something else the library does on its own?