Haha. Yes, I can guess that but it doesn't really behave like a cache folder.
That was my doubt.
It is actually possible if you carefully do the job. It's just importing objects and making them active by changing code to valid references. I imported objects like this and developed two solutions way long back ago. From what I've observed is, for new CSS solutions, if you want same solution ID, you'll get it provided you maintain the same solution description while you create solution. Somehow, SAP's using the soln. description we give to generate solution ID's.