> I don't know how many generations of people breeding it would take to get a selected trait - humans are genetically very similar compared to other species; there is not much variation... so I don't have any idea of what the breeding program length would be, but I assume that it would be several generations

Use whole-genome mutagenesis and increase the size of your population. This will reduce the total number of generations that you require to find the novel mutations that you seek.