Or what if our solar system is really just an atom helping to make up our galaxy which is actually a molecule in someone else's world? Your post reminded of the atom/molecule analogy that I used to wonder about as a kid.
I assume that this line makes a nearly infinite number of possibilities possible, but I also consider that there is a limit to how long these realities will exist. I would also consider the number of realities practically limitless in that respect, with realities that have run their course being absolutely erased successfully to encourage the development of new ones. Although the principle of limitless possibilities will still be fulfilled, I think there would still be some sort of limit as to how many multiverses at any one time could exist. If that is indeed the case, the next issue will be how that will decide the longevity of a multiverse. If these facts were actually endless possibilities, "dimensions" of which the lifetime itself was still infinite would arguably have to be granted. There may be some sort of multiversal superiority, with that being said, in-which said multiverses are preferred over others who do not have some form of extended lifetime.