Nekkid, expept for a bag of gold?

[Steverooo]

1. 1,000 gp, no sp

It's possible, using the treasure tables to end up with all coins being the same time. While this is fine for a single orc or somesuch, it's a bit harder to swallow for a dragon.

The NPC is saving money for something, and converts all change to GPs. The Dragon likes gold, and has a henchman do his banking. The PCs the monster killed only carried gold... Etc.

2. Pounds and pounds of metal

In the example of the devils, each one was carrying 500 coins. That's ten pounds of coinage. Where does this come from? Is it in normal currancy? Why would devils (or trolls, hydras, umber hulks, etc.) have such things?

It comes from victims (unless the NPC is intelligent). Giant Rats don't carry magical Pipes of the Sewers strapped to their backs, but you might find one in their nest, for example.

The currency can be normal, old, ancient, or Diamond-in-Amber Glulditches. It may be extraplanar, or even unique (like the hand-crafted Melnibonean gold wheels). It just doesn't matter!

Devils are intelligent, and they know that these things have value, and give them power among mortals... Why would they throw it away? They could use it to bribe some wench to tempt a Paladin... Umber Hulks, etc., don't clean up after themselves. They kill, drag it to their lair, eat the juicy parts, and throw the rest on the floor. You dig through the detritus, you can find an inedible bag of coins.

3. Wandering monsters

Not directly related to the others, but -- for those who use random encounters ever -- how do you generate treasure for these? Do you pause the game and roll, make it up, prepare "samples" in advance, or something else?

Do it however you like. I prefer to have all treasure rolled up in advance, know where it is, how it's concealed, etc.