This however sounds promising would they stunt each others growth though?
if this is possible what about apple, pear and plum in the same hole? I
think it would be pretty cool if they twined around each other.
Knowing what to google for has thrown some good links up this tree on this
page (dont think its a fruit tree? but it looks good anyway.
http://www.exploratorium.edu/gardeni.../grafting.html