Can I throw in something from left field. There is a plugin for hey0's mod, "poemCredits", which monetises the value of specified items as "credits". It also introduces an ATM system to the game where you can deposit specified items and buy other items. This would enable a number of items to be utilised without the hassle of matching trades or necessarily forcing someone to mine a lot to get the likes of gold. Personally I think I've only got the likes of 3 gold bars from all the mining I've done. So I wonder if gold's a bit too rare to be effective.
Thread here: poemPack mods (Page 1) - Plugins - Hey0's Minecraft Mods
I've downloaded it, but still to test it out locally here.
This adds an in game economy to Minecraft. Depositable items are defined in the shop.txt file. Simply place them in an ATM and right click the block. Purchasable items are listed in the /buy command and is completely customizable by the shop.txt file.
/setatm - Sets a block location where blocks need to be positioned to deposit correctly. See atm.png for example of an atm. As admin, I stool in the gap (on top of the middle brick) of the atm and did /setatm. This sets the location of the ATM to where my feet are. I then finished the ATM by placing the wood blocks on the top and added a sign.
/buy <item> - Doing /buy will list items from the shop.txt. Doing /buy <item> will spawn the item and deduct from your account.
/pay [player] [amount] - This will transfer credits from one player to another.
### shop.txt for poemCredits
# Values below are for currency
# Format is: Coin:ItemID:Value
# Values below are for the shop
# Format is: ItemID:Amount:Cost:Name
1:64:5:Smooth Stone (Stack)
17:64:10:Wood Logs (Stack)
2:64:10:Grassy Dirt (Stack)
78:64:20:Snow Covering (Stack)
48:64:25:Mossy Cobble (Stack)
79:64:30:Ice Block (Stack)