We have a 1/2 husky, 1/2 wolf that has extremely bad separation anxiety.  Whenever we left the house, she would scratch the doors trying to open them and get out to follow us.  I found this cage here on Wayfair.  It arrived very quickly after ordering.  Now, when we have to leave, we can put the dog into this cage.  It is plenty big enough for her - she has room to move around if she wants to.

My only complaint about it is the "floor" section of it.  It seems to hurt her paws - when she is in it, she would constantly lift up her paws like they were hurting.  We put an old comforter in the bottom of it to make it more comfortable for her.  In my opinion, it would be more comfortable for pets with a more closely "knitted" floor bottom, however, I do understand that the reasoning behind its design is for any solid pet waste to be able to go through to the bottom of the tray insert.