Hmm, now you make me doubt, but yeah this is how I did it in the first place when I was dualboxing.

I leveled :
  • pally (recruiter) + mage ("friend")
  • druid (recruiter) + shammy ("friend")
Then with that I could level up toon from 0 to 60 by first granting levels on it from the mage, then from the shammy...

I think I have read somewhere that there is an hidden counter that increases every two levels. So transferring a 60+ toon would give nothing. And also transferring the toon you leveled to another account would make him lose its levels grants as well.

Any third opinion / experience on this to settle the subject ?