I'm in the market for one just in case I need to bring my (big!) BP to the vet's office in the future.

I was at the pet store today and saw some large rodent plastic carrying cases, meant for guineas and bunnies which would probably work just fine. I also saw some large fancy canvas bag's meant for small dogs. Has a nice sturdy bottom and a zip top with mesh around the sides for air vents.

What do you guys use?