I don't see how this can happen until fare structures are aligned. HP and NW's fare structures are totally out of whack, which is what dissolved the CO-HP relationship.

While the CO-HP divorce did suck for me as a west coaster, I understand why CO was unhappy at HP's lower fares being sold on CO-operated flights. CO-HP had a much more extensive codesharing structure than NW-HP does. If NW-HP started a codeshare now, we'd have that sort of tension as well, which is why the NW-HP partnership is limited today. While I see reciprocal Elite benefits as a possibility, a full partnership with codesharing is unlikely at this point.