Originally Posted by
naithantu
What mod are you talking about? A mod shouldn't be able to override the stack limit that minecraft (and therefore the server) has :3
Edit: OT: Don't really see the need for this, many items have already been made stackable in previous minecraft updates, leaving only armour, tools and a couple of barely ever used items (like saddles) non-stackable. Also, it's not possible to properly increase max stacksize. I think (didn't check this, but I'm fairly sure this is sort of how it works) that both the client and the server check stacksize. This means that we can change the server to allow bigger stacks, but in your client you still won't be able to place one saddle on another (could use a command to stack them, but that's quite messy...)