I've said it before, but I think the simple yet effective solution would be akin to Skyrim's. Show the "empty" status when highlighting a container. "Barrel (empty)". That way you can quickly assess which containers are worth searching. At the same time, the containers are still containers and it avoids the problem of "ok, I can SEE the chest, why can't I put anything in it???". (Granted, it's not a big problem, but personally I like when game world objects are consistent.)
In addition, concentrate the loot a bit, so among 20 barrels you have one with 20 gold and another with 10 gold and a cheese wheel rather than 15 barrels of 2 golds each.
The roll idea sounds interesting, but I'm not particularly keen on further increasing the role of RNGesus in the game. I'm quite allergic to random loot, personally.
