I don't quite understand what you ask, but I assume that by stat block you mean how NPC and monster stats are represented and want to make it as small as possible. Personally I just follow the way in which those are given in Monsters of Legend and Elric of Melniboné core rules, with the exception that I don't define full skill set for lesser NPCs and monsters. If I need skill which I haven't defined I can always invent the skill % during the game (based on the general characteristics of the NPC or monster in question).
The way stats are given in Legend/MRQII books is IMHO already optimal, I don't know how you could make it smaller without leaving out important character information.
