I have this carrier, the medium size. I've carried both of my yorkies in it before, and together they would have been just over 8lbs. I decided to get a slightly larger one even though they fit just fine, with being two they needed just a little more room.
It's soft-sided but there are aluminum poles that give it stability. Read about it and if you would like I'll sell you this one for a much cheaper price than you can find it on line. And, I've only used this the one time taking them into the hotel at Chicago.
The Carry Den Pet Carrier