I have kept Tiny(6 1/2lbs yorkie) with Sake(35lbs border collie) in the same large crate once and it didn't work out. Tiny kept picking on Sake and poor Sake was pushed to the back corner of the crate by mean old Tiny.

However, I can crate Sake with Teddy(12lbs yorkie) and they get along fine or I can crate Tiny with Teddy together. Just not Tiny and Sake. I guess Tiny just doesn't like Sake.