Feature suggestion: iswitchb should have an option to show virtual buffers like ido does

[Tom]

I see ido now has a virtual buffers option which shows unopened
matching buffers from the recent files list:


        (defcustom ido-use-virtual-buffers nil
  "If non-nil, refer to past buffers as well as existing ones.
Essentially it works as follows: Say you are visiting a file and
the buffer gets cleaned up by midnight.el.  Later, you want to
switch to that buffer, but find it's no longer open.  With
virtual buffers enabled, the buffer name stays in the buffer
list (using the `ido-virtual' face, and always at the end), and if
you select it, it opens the file back up again.  This allows you
to think less about whether recently opened files are still open
or not.  Most of the time you can quit Emacs, restart, and then
switch to a file buffer that was previously open as if it still
were."



I suggest adding an option to iswitchb to get this behavior.

iswitchb does have an option for virtual buffers, but it shows
them only if there is no match in the list of open buffers
(so if you type "list" then it doesn't show the unopened
file "list-test.c" if, say, there is a "list.c" buffer open):

(defcustom iswitchb-use-virtual-buffers nil
  "If non-nil, refer to past buffers when none match.
..."


ido's version is much more useful, because it completely blurs
the difference between buffer switching and file opening and there is
no need to explicitly open files if you want to switch to a
recently used file.


iswitchb should also support that.