Great Stuff... I just derimmed my 20L as well and was looking for a light setup. I like the look of your light. Is that the same as the Aqueon Corilife? Where did you get the metal brackets for it... It's got a really good look to it.
It is made by Coralife but I believe Aqueon sells and identical fixture under their brand now. Here is how I made the bracket- Talontsiawd's Low Tech 20 Long.....New Pics 8/15/2011
I had a rim on the time so I added some thin strips of high density foam on each side after I derimmed the tank.