How about adding titles that could be appended to your name for various achievements. They could be humorous or serious.
For example:
clare, Alph's best mate (or Alph's brown-noser, or Alph-aholic, etc.)
Rascalmom, the Wanderer (or Street-walker, or Path-prowler, etc.)
For someone who has achieved the highest Tinkering badge:
glitchiepoo, Ubermaster Tinker, or Tinker 1st class
For levels of experience:
Most xp: en, the Wise (or Primus, or the Amazing)
For attaining level 10: Novice
For attaining level 25: Apprentice
For 50: Journeyman
For 75: Master
For 100: Grand Master
When someone has more than one title available to them, they could select the one they wanted to display.