I'm a fan of the buddy belt harness, I really love it, it's made of soft leather, that doesn't tangle the hair, yet it's strong enough to swoop them up, if a large dog is approaching. It also has a buckle, instead of one of those little clasps that have a mind of their own. You say that the dog is 5 pounds, how old is it, is the crate for house breaking or just something you'd like him to sleep in? For housebreaking you want a fairly small crate, with no more room than for them to stand up in and turn around in, so they won't be tempted to pee on one side. If you are using it for longer periods than you want a larger crate, some people use the larger crate for house breaking and just partition off part of it. JesBred gave me this link the other day, she said that they were having a sale on Buddy Belts.
BUDDY BELT HARNESSES *** REGULAR, SPECIAL, FANCY & LUXURY COLORS