Today this beauty arrived from PowerWerx today, the RIGrunner 4008s. I've seen some other R2 projects that have used these and it really makes organizing the power system a cinch.
(PowerWerx's website for these is http://www.powerwerx.com/west-mountain-radio/ )
Initially I wanted to mount it across the top but it is slightly too white for that. However I think vertically will work nicely.