Why not just use a mini U-lock. Even for a 10 minutes lockup it's better than a cable. A Kryptonite Evolution mini weighs only 1.85 pounds, fits into many pants pockets and is Silver Sold Secure rated. Better than any cable lock out there and just as handy. For a "quick" lockup you could even not bother with the Sheldon Brown method (which takes a bit more manipulating of the frame into position) and just lock your top tube to any convenient object. It's still more secure than using a cable lock.