I travel a lot, so travel soap is a standard for me. Originally I bought a guest soap tray mold (with indentations for the cutting) and used those. But now, I just cut small sizes to fit into my travel soap holder. No particular mold is really needed once I decided on the size I prefer for my travels. I wrap them the same as I do my larger soaps - shrink wrap & a mini label. I generally just keep them for myself rather than giving them away, so I don't do the whole label, just the high points to help me recall something specific about the soap on my travels.
I have a good solid plastic mini travel-size soap holder, from where I have no recollection! It's a small version of a larger more common soap holder (such as one may send their kid off to college with for taking to the dorm.) It's really about a perfect size to put one or two (depending on how small or thick) hotel soaps into. I always keep at least one travel bar in it and that lives in my ditty bag in my suitcase. In addition, I pack a couple (or more) new travel soaps for when I finish the other one.
Additionally, every time I travel I also carry with me one or two small travel soap trays (the kind that are self-draining) so that my travel soaps dry quickly. That also lives in my ditty bag in my suitcase.
So I would suggest that first you decide what size seems best for a travel soap, and find a suitable plastic container in which it will fit, then consider including a soap saver of some sort (self-draining soap dish for use while the soap is out of the holder). I would suggest finding a plastic mini travel soap holder that would fit your desired needs and cut soap to fit somewhat loosely. I would not choose tin or metal or anything fragile as hopefully, it will last a long time for many many trips.
As far as leaves of soap inside a container. They look nice in the beginning, but eventually they look like soap powder. Not pretty for long, especially for the seasoned traveler, and even worse if kept in a handbag for any length of time. And I never found those paper thin soap 'leaves' to be enough soap for even a single handwashing event. Seemed like a nice idea, but IME fell short of my expectations.
