I ended up getting this one
https://shopelitegourmet.com/collections/blenders/products/retro-personal-blende?variant=37480050327710
I think it's probably pretty much the same as the Frigidaire one John posted above. It's the same wattage, fits the same glass mug, etc.
I settled on this gourmet elite one because I found reviews specifically talking about using it with standard jars. A few people complained that it leaked when using a standard jar because the rim of the jar/mug it comes with is deeper than jars you buy. According to one review, it fits otherwise so you can just stick an extra gasket in to get a better seal.
Once I got it home, I checked the seal with the old tomato sauce jar I wanted to use for my smoothies. It fit perfectly without an extra gasket. Then I checked with a 125mL canning jar. It fit perfectly, too. So no problem with jar interchangeability.
It's almost twice the wattage of my Hamilton Beach, so it blends way better than what I've been using. I haven't tried it with kale yet, but I'm sure it'll be fine.
Also like the Frigidaire mentioned in this thread, the one I got has the genius design of having the jar disengage from the blades by turning it in the same direction you need to turn the blade assembly to unlock it from the blender base. The first time I blended something, the jar came loose from the blades when I tried to unlock it from the base. I had to flip the whole blender upside down to avoid dumping smoothie all over everything. From then on, I've pushed down on the top of the jar a little bit when I unlock it from the blender base, and I haven't had the jar come loose since. So that's a non-issue so far.
The blades are attached to the plastic base that locks onto the blender, so you can't take them out to clean like you can with my Oster. It's a little tight getting to the underside of the blades, but way better than the blenders that don't come apart at all. I've been using a toothbrush to get under the blades and around the shaft and it works well.
The only thing I don't like so far is that the gasket sits quite tightly in kind of a deep groove in the blade assembly. I have to get the tip of a paring knife if there to pry it up and clean it properly.
Now to see what kind of longevity it has. I've never liked my Hamilton Beach, but it cost something like $12 and it's lasted at least fifteen years, so I've got to give it points for that.