I've seen people make sweaters out of socks for really tiny babies. You can get the fuzzy ones and cut the foot part off and cut little arm holes. I think there is a thread on here somewhere about an argyle sock sweater that turned out really cute.
Maybe you could order something online and have it overnighted?
www.glamourdog.com is a boutique i like to order from. They have a lot of XXS things that would fit a tiny boy.
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~Magnifique Yorkies~
Purchasing from backyard breeders, pet shops, and puppymills perpetuates the suffering of other dogs.
Educate yourself and buy from reputable breeders or rescue.