We are all set for Memphis to ride with me this summer. I purchased the Kuryakyn Pet Palace which is a full, bike mountable carrier and it now doubles as his everyday carrier as well. I never looked for a backpack style but I would suggest checking T-Bags as they do make some motorcycle pet carrier products as well.
We also have doggles for his eyes and you can buy helmets although he is so small I was worried if the helmet caught a gust of wind it could snap his neck.
I would think, if your dog is going to ride between you on the bike a regular backpack dog carrier would work. That you could just google to find one you like.
Good luck and keep the shiny side up!