I have one suggestion:

Tag of clan in tablist before the player name. But, it should work thoose versions 1.5.2 + up
Maybe i can do this soon.

i'm sorry my English, i'm learning, and i'am from Brazil.

Look, as this

Dá uma olhada:
https://github.com/marcelo-mason/SimpleClans/wiki/Displaying-the-clan-tag-on-the-tablist

Legal, eu acho interessante ter este benefício opcional na config, podendo ativar/desativar.
Mas de qualquer forma já que existe plugin para tal vou fechar a sugestão.