pidfile option

I ran a second copy of conserver (specifying a 2nd config file
and port#) to test some things and I discovered the hard way
that there is no way choose an alternate pidfile (at runtime).

I started to look into the source to add a command line option
at realized that both of the obvious choices ('p' and 'P') are
already in use.  Assuming that a patch to add such an option would
be of enough value generally to be put into the official source someday,
is there some command line argument letter that makes more sense than
any other?

John