I have my own idea for a way to get a focus target in a dark scene (where you don't have any restrictions, I'm NOT talking about dark rides here). Laser pointer. I tested it out once and it seemed to work. The idea is that it could work at longer distances where the light from a flashlight might diffuse more. You'd have to hold it still, my test was only close range so it was easier.
Frankly I wish I just had an infinity button. In general my night shots are usually focused to infinity (well, the hyperfocal distance would be better, but I haven't messed around with that yet). I typically do it by finding the farthest light I can, focusing on it, and then switching to manual focus. Normally it's a street light (the street light itself, not the area it illuminates), although once it was a light on a barn a good distance away.
In case you're wondering, this idea IS a ripoff of something Sony used in one of their prosumer digicams. I don't know if they still use it. It projected a laser grid onto your target and used it for focus information. Since I lack a laser grid system I just use a laser pointer spot, I can still focus on it. I've never used it in practice though, I imagine it could get difficult to hold it steady enough and I've typically managed using other means.
