Admittedly, I don't like the bulky, weird animal backpack ones, but that's just me.
I found this wrist connecting one and ordered it without high expectations:
Kinderkord Parent and Child Safety Restraint Set
You know I got it from Amazon right? It was $13.41 (get it here).
This is a product that keeps a parent connected to their child via a wrist band that both the parent and child wear. It reminds me of those thick rubber(ish) watches.
I ordered it when my son was just 20 months old and had no idea how well the child band would fit his tiny wrists, but the smallest adjustment fit him perfectly (and he's a small kid, too).
He never seems that bothered to be wearing it either. That could be because he started getting exposure to it when he was 20 months old, but the cords on each band are retractable and it's awesome to not deal with extra slack. The tug of the retractable cord is very minor - like that of those retractable name badges.
There are a few different lengths to choose from, too. If you connect the two cords together, it's a total of 3 feet in length. You can also connect the parent cord directly to the child wrist band, which takes it down to 2 feet. Or you can connect the child cord directly to the parent band for a length of 1 foot.
I love that this gives curious toddlers an opportunity to be down walking on their own, but also the comfort and safety of not being able to actually wonder off.
I feel it's an ideal "child leash" system, and would recommend it to anyone interested in a product to serve this purpose.
For someone who lives in a big city, it's a must have in my book!