Re: how about a find-library-other-window command?

[Richard Stallman]

    I've wondered in the past whether it would be feasible to have C-x 4 be 
bound to
    a command which reads a key sequence then executes it in another window, so 
that
    we needn't define new commands for every command we want to execute in the 
other
    window.

It is an interesting idea, but we would need a special feature to enable
c-x 4 f to keep working, so you don't have to type C-x 4 C-f.
Some attention may be needed for various help features that use keymaps,
in order to get good results.

So this won't be trivial, but it is worth trying.