I do this myself recently I had a trip to Singapore planned and the prices on Air Canada were very expensive for the dates I needed to travel so I checked the delta website and they had reasonable fares and also a status match program. You can find info about their program here.
All I had to do was send proof that I am an Air Canada elite member, and they confirmed that if I flew over 16,000 miles in the next three months that I would get gold stars on delta. My trip to Singapore was going to be more than that.
So I did the status match and the trip, and now I have Delta Gold status in addition to my Air Canada E75K status until the end of February 2014.
I am not sure if I will fly enough on Delta to keep this but I like to have options.