I visited [Cargo] site, and yes, it seems as if you can (as of today) still purchase a subscription. For $9.97.
This is the cool part: since subscribers will get GQ for the remainder of their subscription (normally a $12/year deal), I'm saving $2.03 by subscribing to the now-defunct Cargo just to get GQ. I'm cheap that way....
I even got confirmation via e-mail.
Which raises the question: Is GQ worth it, even saving $2.03? That's one you'll have to figure out for yourself.