[Fizzlemizz]

It gets roped into the PlayerFrame with the where depending on class and what is showing:

function PlayerFrame_AdjustAttachments()
    if ( not PLAYER_FRAME_CASTBARS_SHOWN ) then
        return;
    end
    if ( PetFrame and PetFrame:IsShown() ) then
        CastingBarFrame:SetPoint("TOP", PetFrame, "BOTTOM", 0, -4);
    elseif ( TotemFrame and TotemFrame:IsShown() ) then
        CastingBarFrame:SetPoint("TOP", TotemFrame, "BOTTOM", 0, 2);
    else
        local _, class = UnitClass("player");
        if ( class == "PALADIN" ) then
            CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, -6);
        elseif ( class == "DRUID" ) then
            if ( EclipseBarFrame and EclipseBarFrame:IsShown() ) then
                CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, -2);
            else
                CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, 10);
            end
        elseif ( class == "PRIEST" and PriestBarFrame:IsShown() ) then
            CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, -2);
        elseif ( class == "DEATHKNIGHT" or class == "WARLOCK" ) then
            CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, 4);
        elseif ( class == "MONK" ) then
            CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, -1);
        else
            CastingBarFrame:SetPoint("TOP", PlayerFrame, "BOTTOM", 0, 10);
        end
    end
end