Why core side? There's an option in aCis.
Just find the item in gameserver\data\xml\items and add...
<set name="is_stackable" val="true" />
Then find some stackable item, i.e. etcitem and change it.
It has nothing to do with the LoginController, but with CharacterCreate... Well, I have the right thing for you, enjoy.
Make sure you add the lines manually cuz it's adapted for my pack that obviously has custom .properties file.
http://pastebin.com/XXZgncvu
None is going to give you his own ideas and features that one wants to realise. You can get a lot of different suggestions like max weapon, armor, jewels, etc... Only. However, I wish you good luck and a lot of success.
Indeed. Nowadays, people's creativity is on very low level. That's because of these free shares. They find everything ready, and they don't even spend 5 minutes ti re-edit it, at least.