The problem with 'designer crosses' such as 'labradoodles' is that their is no intent to create a new breed.To create a new breed pedigrees are crossed and than the pups which have the 'requirements' of the new breed are kept and bred from in turn and the same process repeated until the breed breeds true .
Labradoodle,pugalier,etc breeders just breed crosses....no intention of breeding further generations in an attempt to fix type....hence in answer to your question....never