You could probably whip up stats for a "gold golem."
Here:
Golem, Filthy Lucre; Filthy lucre golem: CR 6; Size L; HD 9d10; hp 75; Init -1; Spd 30 ft; AC 18, touch 8, FF 18; BAB +6/+1; Grapple +15; Atk: +10/+10 melee (2d8 + 4, slams); SA Berserk; SQ Construct traits, damage reduction 5/bludgeoning, darkvision 60 ft., immunity to magic, low-light vision; AL N; SV Fort +3, Ref +2, Will +3; Str 21, Dex 9, Con 0, Int 0, Wis 11, Cha 1.
Skills and Feats: Hide +3.
Special Abilities: Damage Reduction, Darkvision, Low-light Vision.
A filthy lucre golem is a construct designed to guard a wizard's treasure in a unique way - it IS the treasure. It has no possessions and no weapons. It IS possessions. The golem stands 8 feet tall and weighs almost 1000 pounds.
A filthy lucre golem golem cannot speak, although it continously makes the sound of clanking coins and other valuables. It walks in a graceful and determined way. It has no real intelligence, but is somehow magically intelligent enough to walk a set path, and to deviate from that path to avoid thieves. It also is capable of understanding if a party is powerful enough to have a reasonable chance of defeating it, in which case it will try to Hide, which it doesn't do particularly well, being composed of glittery bits.
Combat
Coin Blast (Ex): As a free action every 1d4+1 rounds, the Filthy Lucre Golem can unleash a blast of coins in a 20ft cone, doing 2d6 damage to all in the area of effect (Reflex DC 16 for half). Each time this is used it leaves 2d20 of each type of coin: copper, silver, gold, and platinum resting in the area struck. If a party is forced to flee combat with this creature, each character will find 1d6 random coins in their pockets, folds of clothing, hair, etc.
Immunity to Magic (Ex): A filthy lucre golem is immune to any spell or spell-like ability that allows spell resistance. In addition, certain spells and effects function differently against the creature, as noted below.
A magical attack that deals fire damage in excess of 10 points slows a filthy lucre golem (as the slow spell) for 2d6 rounds, with no saving throw.
Value: When destroyed, the golem collapses into its component treasure (minus any used in the Coin Blast or destroyed in battle). When defeated the filthy lucre golem yields 10,000 + (2d4*100) gp in random coins, gems, and jewelry. (this takes into account the blasts and damage)
Obviously you can boost the coinage, or stick a few items in there for safekeeping. If you do that, I would make it interesting by having those items be forced to save any time they hit the thing with some big (but probably ineffective) spell, or do more than 20 points of (past the reduction damage)..."Nice hit...25 points of damage, and you hear a shattering sound as liquid pours from its side, smelling of healing potion".