I have a 20g L also & just use a cheap single T8.
I've been thinking of upgrading - not for higher light - I don't want to do CO2 - but something sleeker & nicer - just better.
I don't think a single light shows off the fish very well either & my tank is in a rather dark location (basement).
I like what you've done Knox but where my tank is I don't have space to do that.
I kind of like the one from Kens fish.
Eheim Pimp Club #490 Ecco 2232