I don't know if this still works ... but two years back my wife and I (both Silver Elites) showed up for a CO - Alaska Air codeshare, already booked into Coach from Vancouver (YVR) to Anchorage (ANC). At the check-in counter I asked if two FC seats were available for upgrades. The clerk smiled and said "I can give you a Revenue Upgrade for $50 each." And he did!

I don't recall Continental offering Revenue Upgrades for many, many years ... but perhaps Alaska Air still does.