Also, rather than setting generic keys like "unit" on arbitrary frames that don't belong to you (like the UIParent) it's probably better to create an intermediate frame, and parent the RuneFrame to that. Then you don't have to worry about overriding, or being overridden by, other addons or default UI code.
lua Code:
local f = CreateFrame("Frame", "RuneFrameContainer", UIParent)
f:SetSize(130, 18) -- default size of RuneFrame, but doesn't actually matter
f:SetPoint("TOP", UIParent, "CENTER") -- use this to set your desired position
f.unit = "player"
-- set any other things the RuneFrame needs here
RuneFrame:SetParent(f)
RuneFrame:ClearAllPoints()
RuneFrame:SetPoint("TOP", f) -- position the container, not this