I first tried a lovely fluffy dog pillow which worked great till Sydney ate it!
So I put another one just like it in there and well, he ate that one as well.
(I guess I'm a slow learner)
So I decided to just leave the crate bare with just the plastic pull-out tray and you know what, he at that too!
Puppy hood has been a rough ride in the destructive chewing dept.
Well now that he is a bit older (18 mos) I have given him a new crate pad which is about 1 1/2 in thick and this one is doing just fine.
In the end I think anything that is a bit soft will work, just as long as it doesn't get eaten.