I did a lot of digging for retractor part layouts. In the case of the vacuum cleaner cord, it appears that the cord's conductors make contact with a disk-shaped contact, allowing the entire cord to spin without being broken during retraction.
Unfortunately, I don't have a Zip-Linq cable and can't find any shots of the mechanism. It seems to me that they've got to be using a similar method. You have to pull from both ends, meaning that it's got two mechanisms, but you'd have to use the contact disk method to prevent breakage. I may be able to get ahold of a retractable Playstation cable fairly cheap, so I may grab one and crack it open to see how it works.
The thing about using a tape measure is that the end of the tape doesn't have to connect to anything other than the spooling device. With a cable that is going to have power going through it, it has to maintain contact on both ends. Unless you have a method similar to the contact disk, the controller end is only going to act as a brake. It's one thing to wind something up that only connects at one end, such as a cable winch or a tape measure, but when you're working with a power cable that has to connect at both ends, it gets tricky.