How about once you break level 100, you have accessible a "trainer" skill.
With that skill, each time you get it to 100% you can choose a skill or spell
that you already have at 100% and you can serve as the equivalent to the guild
hall for that skill/spell, ie. members of the guild can train or study from
you. That's a SOMEWHAT non-intrusive way to blow mounds of exp that will be
like a HUGE +dicksize for highbies as now newbies can stare in awe at their
instructive prowess, or otherwise come to them to learn.