That's true about the lumens. My point was more about lifetime-you can overdrive the L3, get fairly close to the output of the L5, and still have a fairly decent lifetime. An L3 at 1A puts out 80 lumens. At 1.3A it would put out maybe 25% more, or 100 lumens. The L5 has too short of a lifetime even at 700mA, much less heavily overdriven, to consider using on a bike. For a flashlight, it's fine, but you can rack up hundreds of hours a year on a bike light if you ride a lot. Lifetime is an inversely proportional exponent of LED current-doubling the current might result in 10% of the life or less (the exact function depends upon the type of LED). While worrying about getting 20,000 or 50,000 hours out of a bike light is ludicrous, aiming for a 1000 or 2000 is not. An L5 overdriven at 1.5A would probably only last a few nights, which kind of defeats one of the reasons for using an LED bike light in the first place, the other reasons being greater efficiency, especially when dimmed, and a truer white color (which results in greater visibility per photopic lumen).
It goes without saying here that regardless of which Luxeon is used you need some sort of collimating optics as Luxeons without one are better suited as area lights rather than headlights.