Many lights will be able to illuminate objects in the 400 yard range. It sounds like the AmondoTech L35 ($332) would fit your needs, and there is also the AmondoTech N30 that should be back in stock any time for around $200 that is similar to the L35 but will have a shorter runtime, not be as waterproof, and might be a little less bright. Either of these lights are extremely powerful and will illuminate objects 800 yards away pretty easily.
The other light you should consider is the Stanley HID rechargeable spotlight bought at Wal-Mart for $70. It is a more powerful thrower than either of the two lights mentioned above and will illuminate objects up to 1000 yards away, but will only have a 30 minute runtime and is quite large and bulky compared to the N30 and L35.
One other recommendation I can make is the Dorcy Industrial Rechargeable Xenon Lantern (usually around $40). It is a very lightweight incandescent lantern style flashlight and has a throw of around 500 yards, plus a 4 hour runtime.
If you are looking for the smallest possible solution, then The Dorcy 220 lumen rechargeable CREE XR-E LED flashlight (around $40-$0) will illuminate objects 300 yards away and is very small and lightweight.
Which of these lights appeal most to you? What runtime do you need? Do you need to be able to rapidly turn the light on and off? Do you just need throw, or would you like it also to have a lot of close up flood?
:welcome: