I visited a couple of sims that seemed to be all shopping. Individual stores around some open space.
One had a boardwalk coaster car that you rezzed to move you around the island. There were points were it stopped and you had to get out and look around/shop or rez a new car. Here is a slurl to one store on the sim - http://slurl.com/secondlife/TSUKIJI/65/84/22
One the sim was all black and grays - the sidewalk, the trees. The stores had a little color in the store names that you could see from the streets. Inside the clothes of course provided color. The black/gray background made the colors stand out. Here is a slurl to this sim - http://slurl.com/secondlife/Heartless%20City/134/136/41
One was just a series of open stores around a grassy plot. Felt less permanent than the others. Definitely felt less upscale.
I didn't see any way to know what was on the sim anywhere on these 3 examples - no island directory for instance, although granted, I tp'd into a specific store on each sim and not some central landing zone. You just walked around and looked to see what was there. With SL being slow to rez, that can be kind of aggravating because it seems the store name is often the last thing to rez (kind of like finding your keys in the last place you look). The vast majority of the stores on each of these sims were women's clothing. They're kind of like a RL mall in that. But no game stores or furniture for the most part. All in all, there's not much reason to wander if you came for a specific store - nothing to lead you around the sim.
The exception was the sim with the boardwalk coaster car. That sim had little carts set up all along the waterfront with freebies and cheap things from the merchants on the sim (I think that's what was there - the signs were mostly in Japanese). There were some humorous themed elementsIt also had some machines that seemed to be set up to change RL currency into Lindens.
Here's a view of one of the stores on the Japanese sim with a view out the door
And here's a closeup of the machines you can see out the store's door.