Please could you apply, or nudge upstream to apply, this patch to
xargs that I wrote, adding an option to read filenames from a file
instead of stdin:

http://savannah.gnu.org/patch/?func=detailitem&item_id=2799

For me there are two key use cases for this patch:

1. I can use find to build an mplayer playlist, and then use xargs -a
playlist mplayer without losing keyboard controls in mplayer.

2. If I'm using xargs -a in a script, I can quickly substitute "gdb
--args prog" for "prog" to debug prog in the real-life context that it
is being called. Without the -a option, it would be impossible to do
it this convenient way, because gdb would not be able to read from the
keyboard.

Of course, it's useful for any interactive program that you might want
to call from xargs.