TwinBahamut said:
Setting the new game under a silver standard has nothing to do with absurd twists of fantasy economics and setting verisimilitude, as it simply involves altering the costs in the DMG and the expected value of any given coin.
I think you are the one who missed my point completely, especially since you try to correct me by saying a few things that I have already said (changing the value of the sp to match the old gp).
Why bother changing the value of coins if you are also changing costs in the book? You *have* to do one, but not both, in order to have an appreciable effect on the game.
I'd do the following:
1. There are no gold coins in normal circulation in any quasi-medieval campaign setting. The copper piece becomes a silver penny that represents the basic unit of coinage. Larger transactions can use a silver piece. The only way to have an actual gold piece is to find it in some treasure horde (rarely), mine the ore, or have some other extraordinary means of obtaining them.
2. A 15 gp longsword still costs 15 gp, but you have to lug around 1500 cp or 150 sp to pay for it.
3. Treasure hordes get bumped down one "level" (i.e. if it calls for 1d6x1000 cp and 1d6x100 sp, you simply have 2d6x1000 cp in the horde.)
Basically, without trying to get involved with the craziness of having multiple different types of coins of different denominations, All you have to do is take a cue from the pre-decimal British system - the penny (cp) is the basic coin; 12 pence (cp) = 1 shilling (sp); 20 shillings (sp) = 1 pound (gp) with only the silver penny and shilling (or denominations thereof) being in circulation and no actual gold or silver pounds being minted. Of course, you can use whatever ratio you want (100 cp = 10 sp = 1 gp can still be used).
You *could* have some cultures in your campaign world that *do* use both gold and silver, much like the arab dinar and dirham were used. Interestingly enough, when Mansa Musa, ruler of the Mali Empire, passed through Cairo on his way to the hajj in the 1300's, spending gold like a drunken sailor, he caused rapid inflation in North Africa that lasted over 10 years to recover from - similar things could easily happen in your campaign world.