I want to learn to play the guitar upside-down.  Specifically, I have
a right-handed guitar that I want to play left-handed and I don't want
to restring the guitar.  Are there any resources (books, websites,
etc.) that offer help in learning to play the guitar this way? 
Specifically, I would like to know the best fingerings to use for the
various chords.

its very unlikly that there are many if any resources for this as it
is quite unheard of as far as my knowledge.  it is really quite simple
to restring your guitars, mabye you shoud just do that?

Thanks.  I do agree that restringing a guitar is not that difficult,
but I'm often borrowing guitars and would hate to have to restring a
guitar every time I borrow a friends'.  I'm actually picking it up
pretty quickly (playing upside down) and know other artists have done
so as well, and was just hoping to find a resource or two that could
help me go about it more efficiently.