Quanta? Don't you mean electrums?
Anyways, you could pretty much build any unupgraded deck you want with 4500 electrum. It all depends on your play style.
If you like fast rushes, then there's lots of good options:
Shrieker Rush (Mark of Time, 14 Stone Pillar, 6 Graboid, 6 Shrieker, 4 Earthquake)
Adrenaline Rush (Mark of Life, 12 Emerald Pillar, 6 Horned Frog, 6 Cockatrice, 6 Adrenaline)
Speed Poison (Mark of Water, 12 Bone Pillar, 6 Poison, 6 Chrysoara, 6 Congeal)
Mono-Darkness (Mark of Darkness, 12 Obsidian Pillar, 6 Devourer, 6 Black Dragon, 1 Nightfall, 1 Dusk Mantle, 2 Steal, 2 Drain Life)
Unstable Gas/Fire Bolt Rush (Mark of Fire, 11 Burning Pillar, 7 Wind Pillar, 6 Unstable Gas, 6 Fire Bolt)
Some control-style decks you could try:
Darkness/Earth Denial (Mark of Earth, 12 Obsidian Pillar, 6 Devourer, 6 Black Dragon, 2 Drain Life, 4 Earthquake)
Gravity/Earth Denial (Mark of Earth, 12 Gravity Pillar, 6 Sapphire Charger, 6 Black Hole, 6 Earthquake)
Essence's Mono-Aether:
http://elementscommunity.org/forum/index.php/topic,3154.0.htmlScaredgirl's Time Rainbow:
http://elementscommunity.org/forum/index.php/topic,1615.0.htmlExperiment; have fun.