Ok, how about this one, lets say Naruto progresses in his ability to use Sage mode to the point of having multiple shadow clones all using Sage mode at the same time. Lets say 100 clones.
I think a Henge no Jutsu that merges the clone and any random ninja would be a safe way for them to gain access to Sage chakra. By extension, it could also provide a means of allowing a Sage Kyuubi combo.
I don't think this will happen, but I do believe it can be executed should the need arise. Thoughts?