[Aftermathhqt]

Here's what i'm using and built around nPower code.

local A, C, L = select(2, ...):unpack()
local RuneBar = CreateFrame("Frame")
local DataBars = A["DataBars"]
local Panels = A["Panels"]
 
-- Lib Globals
local select = select
local unpack = unpack
 
-- WoW Globals
local GetRuneCooldown = GetRuneCooldown
local GetTime = GetTime
local UnitClass = UnitClass
local GetSpecialization = GetSpecialization
 
-- Locals
local Class = select(2, UnitClass("player"))
 
-- Color Tabels
local Mult = 2.5
local BloodColor = { 1 * Mult, 0, 0 }
local FrostColor = { 0, 0.35 * Mult, 1 * Mult }
local UnholyColor = { 0.25 * Mult, 0.55 * Mult, 0.10 * Mult }
 
function RuneBar:OnUpdate(Elapsed)
    local Duration = self.Duration + Elapsed
    self.Duration = Duration
    self:SetValue(Duration)
end
 
function RuneBar:Update()
    for i = 1, 6 do 
        local Start, Duration, RuneIsReady = GetRuneCooldown(i)
        if (Start) then         
            self.RunesBars[i].Duration = GetTime() - Start
            self.RunesBars[i]:SetMinMaxValues(0, Duration)
            self.RunesBars[i]:SetScript("OnUpdate", self.OnUpdate)
        else
            self.RunesBars[i]:SetMinMaxValues(0, 1)
            self.RunesBars[i]:SetValue(1)
            self.RunesBars[i]:SetScript("OnUpdate", nil)
        end
    end 
end
 
function RuneBar:UpdateSpec()   
    for i = 1, 6 do
        local GetSpecialization = GetSpecialization()
        if (GetSpecialization == 1) then
            self.RunesBars[i]:SetStatusBarColor(unpack(BloodColor))
        elseif (GetSpecialization == 2) then
            self.RunesBars[i]:SetStatusBarColor(unpack(FrostColor))
        elseif (GetSpecialization == 3) then
            self.RunesBars[i]:SetStatusBarColor(unpack(UnholyColor))
        end
    end
end
 
function RuneBar:OnEvent(event)
    if (event == "RUNE_POWER_UPDATE") then
        self:Update()
    elseif (event == "PLAYER_ENTERING_WORLD" or event == "PLAYER_SPECIALIZATION_CHANGED" or event == "PLAYER_TALENT_UPDATE") then
        self:UpdateSpec()
    end
end
 
function RuneBar:CreateBar()
    local Bar = CreateFrame("StatusBar", nil, UIParent)
    Bar:Size(220, 12)
    Bar:Point("TOP", Panels.ActionBarPanelMiddle, 0, 32)
    
    local RunesBars = {}
 
    for i = 1, 6 do
        local Bars = CreateFrame("StatusBar", nil, Bar)
        Bars:Size(210/6, 12)
        Bars:SetStatusBarTexture(C.Media.Texture)
        Bars:CreateBackdrop()
        Bars:CreateShadow()
        
        if (i == 1) then
            Bars:Point("LEFT", Bar, 2, 0)
        else
            Bars:Point("LEFT", RunesBars[i-1], "RIGHT", 2, 0)
        end
        
        RunesBars[i] = Bars
    end
    
    RegisterStateDriver(Bar, "visibility", "[vehicleui][petbattle] hide; show")
 
    self:RegisterEvent("RUNE_POWER_UPDATE")
    self:RegisterEvent("PLAYER_SPECIALIZATION_CHANGED")
    self:RegisterEvent("PLAYER_TALENT_UPDATE")
    self:RegisterEvent("PLAYER_REGEN_ENABLED")
    self:RegisterEvent("PLAYER_REGEN_DISABLED")
    self:RegisterEvent("PLAYER_ENTERING_WORLD")
    self:SetScript("OnEvent", self.OnEvent)
    
    self.Bar = Bar
    self.RunesBars = RunesBars
end
 
function RuneBar:Enable()
    if not (C.DataBars.RuneBar) or (Class ~= "DEATHKNIGHT") then
        return
    end
 
    self:CreateBar()
end
 
DataBars.RuneBar = RuneBar