I think so, I'm not that familiar with superflux. The CREE get around 73 lumens per watt, and they totally changed the flashlight game when they came out last fall. They instantly made incandescents obsolete, IMO, just changed everything. Put a CREE drop-in replacement/upgrade in a maglight and you'll be getting 2-3x the output for 2-3x longer, at least. Now Lumileds/Philips is coming out with a new 100 lumen/watt LED, the Rebel 100, thats just now (as in, this month) hitting the shelves with the new Fenixes.

You can make them as bright as you want, its just based on your power source and regulation circuitry. That one guy I linked to, I think he overdrives his to get, like 200 lumens output from each Cree. DealExtreme has some cool 5-mode regulators, so you can get hi/low/strobe functions on there.

I don't know what I was thinking earlier about putting the AAs in the handlebars, thats actually pretty ridiculous ha. I got carried away with my scheming. You'd probably want to mount only the LED/regulator assembly in the copper housing that actually goes on the bullhorns, the run a cord down to a small Neoprene sack (like, one of those neoprene sunglass pouches) attached to the water bottle cage, or in seatbag or somethings, that has your batteries and switch. Definitely want NiMh rechargeables too.

edit: oh, and definitely use copper for the led/reflector housing, because it acts as a heat sink, which you need because these things get real hot. If you try and use PVC or something like that, after 10 minutes runtime you'll have some crispy/dead LEDs. And maybe a small fire.