I haven’t, but I feel your pain looking for an alternative!
I can’t help but think it would have to be very well prepared to get the little beasts out of it. Also, I’m not sure if you mean the old metal ice cube trays, with the big pull lever in the middle, or the “regular” kind that you twist to get them out. Af course, there’s the ones will the many, many tiny caveties, too. All seem like they’d be hard to get teh caramels out (except if there were silicone). Also, I think it would be hard to get the caramel IN if there were much space between the caveties.
What I do with my caramels is line a 1/4 sheet pan (so I can lift out the caramels) when they are the perfect temperature for cutting (you just sort of have to try it), and then I cut them with a pizza cutter into long strips, then each stirp into caramels. I keep most of them in the fridge in as much a single layer as possible while wrapping a couple dozen or so—don’t let teh dozen touch each other, because they get softer and really wan tto stick.