I got a UBH and it is a nice set-up (considering all the available battery options.) I currently don't have a head for mine yet (plan on E2C and SF turbo head with MN16 but it can be set-up in a variety of ways as said above.
I think someone on this forum made a cell extender for the E series lights (think Dspeck?) at one time or another. But I recommend the UBH, more options /ubbthreads/images/graemlins/smile.gif