ditto on that Silver John's guitar...
saving the world from evil..silver strung...
we once did a play commemorating him..
the Ballad of Silver John...great stuff!

also, this just in from the giant guitar collections..

http://www.brucegray.com/htmlfolder/html_subpages/guitarsteel.html
http://gallery.michaelandkrissy.com/v/Weddings/wankwedding/IMG_1440.jpg.html
http://www.roadsideamerica.com/roger/QueryTips.php3?tip_AttractionName=guitar&tip_Town=&tip_State=&Submit=Go+Roger!
http://www.sparkspin.btinternet.co.uk/vaster.htm
http://www.exploratory.org.uk/building/giant_guitar.htm
ok this is the last one..a gialnt elvis guitar...check here:
http://www.boogiehouse.com/tup_page_1.html