Arc6s turn up in the Marketplace and can be found floating in the Bay of E on occasion. Might want to set up an automatic search for "arc6 flashlight" and see what you get.
If I had to venture a guess as to what's going on with Arc, I'd guess that they've hit the end of their current manufacturing run and are repairing and selling the ones that got sent back with defects while they wait for the next manufacturing run to finish. This is my guess because I bought two, about a year apart, and the first one is #4160 while the second one is number #0040 and has what is pretty clearly a prototype bezel. But it's all speculation, I have no "inside scoop" or anything like that. Either way I think it's a safe bet things will sort themselves out in the next few months, with one easily-guessed outcome or another.
Anyway, if you can manage to get your hands on a functioning Arc6 head and put it to use the way I described, I think you'll be quite pleased with it. Failing that, the SunDrop is the next-shortest option, and fitted with a Haiku light engine it should do quite well as long as you're not using it as a searchlight. The Haiku XR-E light engine might have better throw on account of the emitter's narrower beam, but I'll have to defer to other people's firsthand experience on that point.