I'd suggest:
1. Properly set clan ranks, with customizable names.
2. Clan warehouse (guild bank) able to take both items and money, with each clan rank having different set of rights (basic member/initiate - only allowed to put items and money in, senior member - able to put in items, money, able to take out certain items (basic stuff like logs, coal, ore), veterans - able to put in items, money, able to take out bots)
3. Clan signature that would fly on a small flag, nothing extravagant, with 100+ pre-set symbols and colours.
thanks.