I think alaska is going to need a much, much bigger presence in ORD before they'd even consider their own board room.
Realistically, AS would have to expand ORD service out of non-hubs to beef up their presence in ORD (probably starting some combination of AUS, SJC, SFO or LAX-ORD). I just don't see a combination of SEA/PDX/ANC-ORD having enough traffic to sustain a Board Room, even if AS just dumped more capacity JUST on those routes. That's kind of declaring war on a major codeshare partner, and it would probably lose buckets of money, since AA would likely fight back- plus there's the matter of gate utilization. As VX could tell you, AA and UA don't exactly welcome competitors to ORD with open arms and friendly grins.