The Tecnica back pack works great for carrying boots. Here's a bag that will work great for bringing your boots and gear on a trip. It's really designed as a back pack but the main compartment is large enough for boots so it can be a boot bag too.

Tecnica Boot Bag Backpack (2011) Features

• Pockets: 10 outside pockets allow you to organize and carry plenty of items.
  
• A small fleeced lined zippered compartment on top to store things like cell phones, wallets and mp3 players and has a cord opening for your earphones.
  
• Tough 600D Polyester for durability and has a waterproof backing.
  
• Spacious U-shaped zippered main compartment can carry boots up to size 12 with other items.
  
• Interior padded sleeve can hold a 17" laptop computer.
  
• Boot straps. Two outer straps will hold your boots outside your back pack and the straps store away in zippered pockets when not in use.
  
• Padded back
  
• Padded back pack straps
• Heavy duty zippers 2-way zippers
• 20.0"h x 13.0"w x 8.0"d.
  
• Weight: 2 Lbs 2 Oz.