I believe you can transfer a character and receive granted levels on that character but not transfer a character and then grant levels from that character.

From the FAQ :

If I transfer a character with unused level-ups to another realm, will that character get to keep the level-ups?
No. Unclaimed levels are not moved during a character copy or transfer. Be sure to use them before you transfer.


Now note that is talking about transfer to another realm, but I take that as strongly implying that Joe Shammy, L60 with 29 levels to grant, can't transfer to another account and grant those levels to a lowbie on whichever account is linked to the account Joe just transferred to.

On the other hand, this I could see being possible:
I have my main account unlinked and I have 4 chain linked accounts A>B>C>D that have run 4 toons to 60, so they have grantable levels (A is linked back to my best friend's account). Now let's say I have a L30 toon on my main account I don't want to reroll (he has rare recipes or sentimental value). Say I transfer that L30 to account A, my belief is that the L30 would be eligible to receive granted levels from the 60 on account B so long as the normal conditions were in place.