Now that so many DSLRs have video capability, more and more emphasis is being put on quality on-camera constant light sources. Now instead of juggling 2 light sources, you can use 1: Dot Line's LED Panel for Speedlites.
The light straps to your flash like a bounce card but this one has 60 5600K LEDs (switchable to 30) built in. If you want to shoot video simply flip the panel down over your flash tube. The LED Panel for Speedlights runs on 4 AA batteries and features a built-in diffuser and a gel holder.