Vapor 2X Pro gear is nice but overpriced for what you get. However, if you want the absolutely lightest gear on the market there are very few options available that can compete. STX RX3 shoulders and elbow pads are good. I am not a fan of their pants or shinguards. Vapor 1X Lite gear is also light and can be found for decent pricing.
If it was me, I would recommend the following, taking into account weight, cost and fitment.
Shoulder Pads: STX RX3, Bauer Vapor 1X Lite, CCM Crazy Light, Bauer Vapor 2X Pro, CCM FT1
Pants: CCM Crazy Light, Bauer Vapor 1X Lite, Bauer Vapor 2X Pro, CCM FT1
Shin: Bauer Vapor 2X Pro, CCM Crazy Light, CCM FT1, Bauer Vapor 1X Lite
Gloves: Bauer Vapor 1X Lite Pro, CCM Crazy Light, CCM FT1, Bauer Vapor 2X Pro, STX RX3
Elbow Pads: STX RX3, Bauer Vapor 2X Pro, CCM Crazy Light, Bauer Vapor 2X Pro, CCM FT1