It only seems right when being asked to venture deep into the dark dungeons that a medeival hero be allowed to bring a sling of torches. I think it would add some cool visual to the game as well as some possible benefits. It is a perfect item to equip to the offhand and should be available to every class. I think carrying a torch should come with some D&D benefits such as:
You could actually attack with it... although it should be fairly difficult to land a successful blow. 1d4 damage + 1d4 fire damage perhaps.
+1 search bonus when holding a torch, c'mon it's only fair...lighting.
On the other hand, hide and sneak features should be unusable when holding a torch..your basically holding a gigantic flare.
In D&D (and in the real world) some monsters are naturally afraid of fire. Since we already have the bluff feature, it could work similar to a weak bluff by causing certain monsters such as dogs, or perhaps even kobolds, to naturally want to avoid morso a player with a torch. This would make it a valued item for spellcasters.
Torches should be timed to burn about 10 minutes I would say and then burn out and be unusable.
Optional: It would be cool if you could burn breakable boxes as well with a torch...say have them burn about a min, then be scraps. You could use this to light up rooms which in turn should help reveal hidden enemies. I would actually prefer it though if players as well as monsters could acually get burned when touching or walking on or through burning boxes.
Burning boxes could also create a certain amount of smoke adding some interesting battle scenarios where negatives are taken on attacks when engulfed in too much smoke...range attacks should take huge negatives trying to shoot through or at a character submerged in smoke.
Anyway, just some general adeas to play with environmental minipulation. If nothing else, a basic torch with some lighting benefits and severely handicapped second hand weapon option could be cool.