Chinese tallow (Sapium sebiferum) is not native but rather an imported species from South East asia and Southern China and as such this thread should be moved to deciduous trees. Sapium sebiferum has not been used much for bonsai but I have seen one or two attempted examples over the years. They exhibit all of the characteristics (leaf reduction, budding back, root working, etc....) needed for bonsai. As you say, it does have a wonerful display of fire Red leaves in the Fall. Collecting from the wild is quite doable if one can find good examples to take. I think the problem with this tree has always been one of which style to use. In my mind it is not suitable for the traditional forms (formal or informal upright or multi-tree) but it certainly would make a wonderful quasi-natural style. I say quasi-natural style because the actuall natural style of t his tree is rather "lolli-pop" shaped but with some work, a better visual effect can be had. I would love to see more examples of this tree used for bonsai and maybe with the abundance of seedlings avaliable where it is capable of being grown (warmer climates of the West, South West, South Central and South Eastern US) we will see some in future years. I would bet there are some good examples in Southern Califormia Bonsai collections that have never been seen by the general Bonsai Community.
Boaz, Kentucky US growing zone 6A