If you need sliding collisions, so far the only way is non-rotated collisions (i'm working on it though). As far as object collisions, I'd say the fastest way would probably be rotated collision boxes. Like you said, you could just make another object representing the collision zones, but instead of moving your main model around, hide and move this one around and just set your actual model as kindof a 'skin' that is always on top of it, pointing in the same direction. This is a possable route I would take.
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