www.Japan-Toy.com has a decent selection and will ship overseas. You are going to have a hard time finding a wholesaler, but if you are willing to buy in bulk, you can contact that site and they might be willing to give a discount.
Thanks for the recommendation...hmm...my brother is a collector of japan toys.."i think he is absolutely crazy for it" ..he has a museum of Gundam toys in a "store room = Museum", he is planning to import toys from Japan and start doing business on it...
I still wondering why guys having so much desire on this toys.. ^@^
I went to the now-defunct Bandai Museum three years ago and the Gundam items are cool. Your brother may want to contact Bandai directly. They could steer your brother in the right direction.