An elongated LED lighting system, comprising: vertical upright supports (240, 242); substantially parallel rows of first and second support brackets (220, 230) connecting the vertical upright supports; and an elongated LED lighting unit comprising: an elongated transparent housing with a first endcap that is free of an electrical connector and a second endcap that comprises an electrical connector; the first endcap, the second endcap, and the elongated transparent housing enclose a plurality of solid state lighting devices fixed to an elongated heat sink, wherein the elongated heat sink (i) extends beyond a first end of the elongated transparent housing, (ii) extends past a sealing surface of the first endcap, and (iii) contacts an internal surface in the first endcap, (iv) extends beyond a second end of the elongated transparent housing, (v) extends past a sealing surface in the second endcap, and (vi) contacts an internal surface in the second endcap; wherein the first endcap comprises an external cooperative surface and an external mating feature positioned onto a corresponding mating feature and surface of the first support bracket, the first endcap has an internal surface that overlaps a portion of the first end of the transparent housing; and wherein the second endcap comprises an external cooperative surface and an electrical feedthrough positioned onto a corresponding mating feature and surface of the second support bracket, the second endcap has an internal surface that overlaps a portion of the second end of the transparent housing. vertical upright supports (240, 242); substantially parallel rows of first and second support brackets (220, 230) connecting the vertical upright supports; and an elongated LED lighting unit comprising: an elongated transparent housing with a first endcap that is free of an electrical connector and a second endcap that comprises an electrical connector; the first endcap, the second endcap, and the elongated transparent housing enclose a plurality of solid state lighting devices fixed to an elongated heat sink, wherein the elongated heat sink (i) extends beyond a first end of the elongated transparent housing, (ii) extends past a sealing surface of the first endcap, and (iii) contacts an internal surface in the first endcap, (iv) extends beyond a second end of the elongated transparent housing, (v) extends past a sealing surface in the second endcap, and (vi) contacts an internal surface in the second endcap; wherein the first endcap comprises an external cooperative surface and an external mating feature positioned onto a corresponding mating feature and surface of the first support bracket, the first endcap has an internal surface that overlaps a portion of the first end of the transparent housing; and wherein the second endcap comprises an external cooperative surface and an electrical feedthrough positioned onto a corresponding mating feature and surface of the second support bracket, the second endcap has an internal surface that overlaps a portion of the second end of the transparent housing. an elongated transparent housing with a first endcap that is free of an electrical connector and a second endcap that comprises an electrical connector; the first endcap, the second endcap, and the elongated transparent housing enclose a plurality of solid state lighting devices fixed to an elongated heat sink, wherein the elongated heat sink (i) extends beyond a first end of the elongated transparent housing, (ii) extends past a sealing surface of the first endcap, and (iii) contacts an internal surface in the first endcap, (iv) extends beyond a second end of the elongated transparent housing, (v) extends past a sealing surface in the second endcap, and (vi) contacts an internal surface in the second endcap; wherein the first endcap comprises an external cooperative surface and an external mating feature positioned onto a corresponding mating feature and surface of the first support bracket, the first endcap has an internal surface that overlaps a portion of the first end of the transparent housing; and wherein the second endcap comprises an external cooperative surface and an electrical feedthrough positioned onto a corresponding mating feature and surface of the second support bracket, the second endcap has an internal surface that overlaps a portion of the second end of the transparent housing.