If I understand correctly, the late Michio Hikitsuchi sensei supposedly received a "scroll of transmission" from the founder of aikido for aiki bojutsu. I have been taught the first two bo kata (bo ikkyo, bo nikyo) from Linda Holiday sensei a while back, although I can't say I could reproduce it today with much success. Others like Clint George sensei and Tom Read sensei (who has a website at www.aikibojutsu.com
on his system) also teach bo kata and such in their aikido.
Saotome sensei also has paired weapons work with bo in his patrol kata which I have also done as well. Interesting stuff, especially when compared with the movements of the jo...
Hope that helps,