John 3:16 is selling Eneloops in packs of 4. Can't remember the pricing.
My take on this Eneloop vs Powerex is this:
If you're a heavy flash user who needs fast recycle throughout a long event, go with the Powerex.
If you seldom use flash, but do bring it about and use it when there's a need for it, go with the Eneloops.
Eneloops can take events too. Earlier this year i did an entire day of shooting of 'Spring in the City' with a single set of Eneloops. Flash set to manual and fired on, many with multi-bursts. At the end of the day clocked over 700 shots with still some juice to take some more.