Does anyone know of an addon that will let me set up two different UIs for the same toon, and that I can switch between with very little effort (like clicking one button)?
If your mod allows profiles, there is usually a way to switch that. If you are talking about your two specs, you could always make a macro like:
/script SetActiveTalentGroup(2);
/script UseEquipmentSet("MyMoonkinShit");
/grid setActiveProfile("whatever");
/clique setActiveProfile("whatever");
...etc
I made up those last 2 lines, but I'm sure there is a command interface to profile switching.
-j