I absolutely agree that would and had CAN go together particularly when expressing/stressing a past event which also ended in the past - it is after all merely the combination of subjunctive + past perfect. The following case sounds fine to my Midwest American (long lived in English) ears:
Policeman to woman: "Was your husband home at the time of the robbery?"
Woman: "No, he would had gone out by that time." (i.e. I'm not sure as I wasn't there either, but I'm almost certain that based on his normal actions he probably was not at home.)