I think this Hand of Glory magic item is cool and it seems especially apropos for an Adventurer Conqueror King campaign where neither dwarves nor elves have anything like infravision. Here's a puzzle: by the rules, how much might such a item cost cost in a typical ACKS campaign? Is 500 g.p. about right or is it off by quite a bit?
Even if it's prohibitively expensive, I'm going to add a few as found-treasure to my game. I agree with the reasons infra/dark vision is nonexistent for ACKS core classes, but I love it when a Thief-type class scouts ahead. Expendible one-use magic items are awesome because; scare resources make for interesting decisions.