I was thinking about those hollows too. I am not a manga reader (although I have been tempted, for my excitement to find out what happens starts to get to me around Saturday evening), but I do have some wild speculation to contribute. Perhaps like Bud said, that Hueco Mundo has some pretty powerful players (i.e. Menos Grande). Going further, hollows could have a system analogus to SS in that there are Captain-like hollows with powerful abilities and/or weapons (kinda like soul slayers with their shikai and bankai). Therefore, the 13 squads could be matched in both strength and number by hollows. This would fulfill a commonly used theme in anime/movies/novels dealing with 'balance'. Perhaps Ichigo represents a loss somehow of the balance. Maybe there'll be a new threat beyond the SS that would tip the scales back. I guess time will tell. Speaking of which...SUB, SUB, SUB, SUB...can't wait for 56!