1. There is some being, x, with some degree of goodness.
2. The simplest theory of reality does not include an infinite hierarchy of beings.
3. The simplest theory of reality is probably true.
4. If (1)-(3), then there probably are not infinitely many beings better than x.
5. If there probably are not infinitely many beings better than x, then there probably is at least one best being.*
6. A perfect being is the simplest and least arbitrary sort of best being.
7. If (6), then probably the best theory of a best being is that it is perfect.
8. The best theory of something is probably true.
9. Therefore, there probably is a perfect being.

*There might be multiple beings that share the highest place in the hierarchy.

Similar sorts of arguments can be run for the existence of (a) being(s) that is/are perfectly powerful, perfectly knowledgeable, perfectly desirable, perfectly teleological, and so on.