We are already aware of the Summoners Rift and the Crystal Scar with it's 5v5 set up and the Twisted Tree-line with the 3v3 style, but it's all based on a teamwork and working together, but what about showing off your own personal skills agaisnt foes coming from all angles? Always watching your back, alone in the midst of battle, experiencing true fear and desperation. A Battle Royale system on an open map much like the Rift or the Tree-line.
The game would consist of 4-6 people, no teams, no help, and no trust. Summoners will spawn at their own respective fountains located around the map. Pressing 'B' will send you back to your own base and stepping onto any one of your enemies Bases will have the usual result in getting blasted by the Fountain Turret. The Jungle will be vast with plenty of choke points and area's to set up traps. Ward placement would be Key in attaining victory.
Each of the summoners base platforms will have 2 turrets protecting their nexus. I don't think that Inhibitors would be really necessary in this type of battle arena. Victory is achieved by slaying enemies you encouter while roaming the jungle with a set of 6 minions as your backup. 3 battle minions and 3 spell caster minions. The point of it would be to take out the enemy turret and destroy their nexus. Battle will be the same as usual, slay an enemy champion to gain experience and gold, upgrade your build and become master strategist. With no teams, you will be able to target whomever you want, but you will also be targeted yourself. Using the /all chat, enemies can communicate and for temporary 'alliances' to weed out the weaker enemy champions.
Once both of your turrets are taken out and your nexus is destroyed, you will become 'Out of Play' and spectate or leave the game if you wish. This is how a winner will be determined. While 'Alliances' can be formed to take out weaker enemies, these bonds are frail due to the fact that at any time your bond could break and you will be stabbed in the back. REMEMBER, there is no trust within this field.
This is just a concept i've been thinking about and i think it really does have some potential as a real field of justice.