Seedlings to Stars just put out their list for the Astros farm system. They took a different perspective, as they identified the top player at each position. As for the system as a whole, here's the gist:
Position Player Upside: C+ Position Player Depth: C Pitching Upside: C+ Pitching Depth: B System Grade: C+
I'm planning a prospect preview of my own, so I won't add any commentary to this.