What about like an in-game tool to save, let's say up to 10 builds for each character? It displays what secondary class you need, you change to that class, click it and it changes from one skill set to another.
Would look like this:
Slot #, Name (you chose that), Skill bar, Secondary Class
[1] Tainted PvP [skill bar here] Elementalist [2] Orders PvP [skill bar here] Monk [2] Orders PvE [skill bar here] Monk [4] Echo SS [skill bar here] Mesmer