Like radioactive giraffes, guitars have been sprouting extra necks for some time now. Witness Jimmy Page's double neck SG on live versions of “Stairway To Heaven” or the guy out of Cheap Trick with his many-necked guitar. Some guitarists have exploited the extra necks to musical effect, like ambidextrous virtuoso Michael Angelo.
But the pinnacle of multi-necked madness has surely been reached by artist Yoshihiko Satoh. Satoh pushes the concept of the to the limit in his 2002 creation "Present Arms". It's a huge amalgamation of 12 lake placid blue Stratocasters, made for the Japanese Kirin Brewery Art Award. Another variation on this theme are his 12 guitar windmills "The Arms", exhibited along with the original "Present Arms" in 2003.
They should be playable on some sort of stand. With 12 necks you would have one for every month of the year, or you could get a few friends to join you in a jam session.