One big difference between regular and epic quads is that many commander effects that are worthwhile in 200 points are far less valuable in 500. For example, an Eye of Gruumsh/Orc Champ quad's extra 5 damage per blow is significant in 200 point play, but not nearly as much in 500.

The sweet spot in 500 points for quad hitters should be around 100 points per mini. That allows you to have four such hitters and 100 points left over for tech and a solid commander.

Most of the LG's potential beaters in this category tend to do too little damage or have too low a hit chance for their cost; in epic play, where you will often see minis with AC 26+, having a primary attack bonus less than, say, +16 is not good; ideally it should be around +20 or more. For LG, the best figures in this range are the Marut (74 points) and the Solar (105 points). The first suffers from its low hit points, which makes it a quick kill against most epic bands, and having a bodyguard isn't nearly as effective as in 200 point play. The solar is decent, but is a commander, so it won't benefit from others' commander effects, meaning you won't get as much synergy as a quad band should have.

For CG there are even fewer options available: the Centaur Hero (78 points) is marginal; Epic Guenhwyvar doesn't do enough damage; Epic Rikka (143 points) is good, but you can only have one of her. Dual Storm Archers and Dual Epic Griffon Cavalry bands are solid, but these minis are too expensive to form a solid quad or even three-hitter band.

CE has some interesting choices, such as the Marilith (73 points, but damage level and attack bonuses are on the low side) and Balor (damage a bit low and is a commander, so no synergy). The Fomorian (119 points) is a solid hitter for a tri-hitter band, but with its huge-size base it is difficult to bring them all to bear at once against a single foe. The Githyanki Dragon Knight (98 points) might be worth consideration though, especially with Vaaklith and possibly the Large Red Dragon.

The LE faction has IMO the best options right now for a quad hitter epic band, including the Aspects of Hextor, Nerull, and Bane; the Horned Devil, the Fire Giant Forgepriest, the Iron Golem, War Troll, Thaskor, the Cadaver Collector, and the Pit Fiend. The Fire Giant Forgepriest in particular looks promising for a quad hitter epic band, since it grants magic damage to things like the Iron Golem and Cadaver Collector that otherwise could not get it.