Have you guys looked at
OPie? I’m not sure there’s a way to have WoW show a different bar or different buttons from the same action (like right-clicking a certain spot) depending on what kind of target you have. If you have to use different actions to open different bars (like right-click for spells you want to use on enemy mobs, or alt-click for spells you want to use on friendly players) then you could probably just use OPie, if you’re okay with the buttons being arranged in circles. It has an option to pop up the buttons at your cursor, so you could just alt-click over a friendly player to have it pop up a ring of buttons.
