http://www.shibarescue.org/
I had never heard of Shiba, but according to this web-site, you may have trouble having two boss dogs in the family! I would do some research on both breeds. Good luck with your decision!
# In their eyes, Shibas can take on the world no matter how big the foe or the task. They are dominant with other dogs and do not usually get along well with other "bossy" dogs of the same sex. Many Shibas will, however, get along great with another dog or cat that agrees the Shiba is boss.
# Shibas can be runners. The Shiba Inu is a natural hunter. Given a chance, Shibas will take off in search of game. It is advisable to never trust your Shiba off-lead unless in a fenced yard.
# The Shiba's least favorite word is "come." They will usually take your number and get back to you, when called.
# Shibas have a mind of their own. While it is possible to obedience train a Shiba, it is a challenge. Tell him to sit and he sits . . . sometimes. If there is something in it for him, and it is convenient at the time.
# Shibas always like to be in charge; their favorite word is "mine." Although not "barky" dogs, they do yodel and scream anytime they feel they are being violated, such as nail trimming, bathing, and leash training.