If there is one thing about having a planted aquarium that bugs me it is lighting. I wanted to get away from tube lighting and go with screw in CFL lighting the only problem is, is finding a screw in lighting system for any tank bigger then 10 gallons is next to impossible, so next idea is the retrofit my current hood but I didn't really want to do that because I might want it for something else, so now I had to start from scratch. I was lucky enough to find the two post below which sent me in the right direction. The hood you see in the directions in this post is actually the 2nd light I have built the parts I don't mention here is the custom cutting I did to the rain gutter and the ends to make it fit perfectly.
Thanks to these two post for reference and the general design ideas; 20L planted light fixture revamp (pic heavy) How to retrofit your light for cheap
Vinyl Rain Gutter
Vinyl Rain Gutter End Caps
Power Extension Cord
Dual Light socket
1/4" Washers x2
1/4" Lock Washers x2
1/4" Nuts x4-5
Spray Paint (Optional)
Cut the gutter to correct size and drill holes for the 1/4" screw that will hold the light socket, the power cord and the switch.
Paint (optional, but will stop the bleed through of the lights through the white gutter)
Take your dual light socket apart and remove the unnecessary parts on the outside, grind your 1/4" screw down so it will fit in the narrow space that the hole is in.
Reassemble light socket with screw inside, use extra nuts to create spacers between the socket and the light gutter so the light dose not touch the gutter or the bottom. Use the hardware in the configuration in the picture.
Insert all the components into the rain gutter; socket, switch, grommet then power cord (before hand cutting the outlets off the end of the power cord and stripping the wire back).
Wire it all up with the heat shrink ready. (might want to test it at this point before you seal the wires to make sure it works)
Cut the screw down to the correct size
Use something to keep the wires in place away from the lights (my case silicone caulk)