Dan Jacobson wrote:

> Hitting RET on a line in the *Process List* buffer should take one to
> that process's buffer, if any.

One way you could do that would be to temporarily bind temp-buffer-show-hook

in list-processes.  I don't know to do that in C, though, so I experimented
by advising it (which works if you call it via `M-x list-processes').  The
new hook function has to parse the *Process List* buffer, which is kind of
nasty because the Proc and Buffer columns can be arbitrary strings (including
spaces) and may be shifted to the right.  (The *Completions* buffer used to
have the same problem, but now you can use the mouse-face property to find
the individual items.)  Anyway, here's a hack to get you started: