gonehuntingagain
TDR MEMBER
You could get another lab. It may be harder to determine if one will be agressive or not. I have a lab (male), and like yours, he will help someone load their truck, however, my friends have female labs, and they are very agressive. They will bark if someone comes up to the house. I don't kow if this is because they are female, but out of the 4 female labs that my buddies own, all 4 are agressive in this way. They are really aggressive hunters too. It might be worth your time to talk to a breeder about this. If you are looking for a chessie, there are some Chessie breeders in the northwest too. There is a breeders list here: http://www.amchessieclub.org/breeders.html
Good Luck
Good Luck