Frank, I'd love to hear 'em!
You're right: it sounds like it's just about the same mechanism as a retractable dog leash. But to me it's one of those, "Why didn't I think of that?" ideas. In fact, the day before I saw it on Youtube, I thought about making the same thing. Then, BAM, there it was. Thanks to Tharkun, I can buy it instead of building it myself.
I already received a shipping notice that says it's supposed to arrive this Wednesday. 3 business days from France. Damn that's fast! I elected the cheap, default shipping option.
Also, great customer service so far. They personally emailed me installation and user instructions and replied to my question within minutes.