Eric-
Being an owner of much of the spectrum of SureFire product line (with multiple 3P, E1, 6P, E2e, 6Z, Z3, 9AN, M6 in the collection--not even including weapons-mounted SureFire I have), I'd have to first inquire what you want your "biger" SureFire to do.
Want to really "wow'em", there's nothing like the M6 (user switchable 500 lu./250 lu. lamp assemblies).
PROS: Lots o'Light, Cooling fins mean no auto-shutdown. CONS: Very Pricey, and limited applications, expensive in terms of batteries for heavy user, Not rechargeable.
Want "wow" factor, but actually economical and very practical to use? Definitely go with the 9AN system of rechargeable Ni-Cad batteries and dual-lamp assembly (40 lu./120 lu. in one!).
PROS: Extremely versatile, Rechargeable, Rugged. CONS: Pricey, requires AC/DC-source for recharging.
Not a heavy user, but want to step up to the 9V without the rather hefty investment of a 9AN, then go with a Z3.
PROS: More usage time, a bit more lumens than 6V-series. CONS: Not that much more lumens than 6V, Not rechargeable.
From 6P to E2e is not really much of a step up. Small package, yes, but not much more power in terms of illumination.
My new favorite? Has to be the versatile 9AN. I find I can use the 40 lu. output around the house a great deal (2 hr. 26 min. run time on one charge by my last test!), and can instantaneously with a turn of the lamp bezel get 140 lu. (for about 20 min.) if I have to say spot something in the backyard. With spare battery always in the charger, I have no down time.
Anyway, hope that helps a little...