Well, I've been reading some articles about new champions concepts so I decided I'd give it a try.
Name: (No idea yet, hearing suggestions :P)
Concept: The idea of this champion is pretty simple, a mecha-kind of champion that moves on a chain track. By moving on this track, he creates and stores Charge. The generation of charged is based on it's passive, and it is the main advantage/drawback of this champion. Using it effectively depends on your ability to gain and use charge, making it range from extremely useful to absolutely obsolete.
Charge (Innate Ability): As (name of the champion) moves, it's chain track generates charge, gaining 1 stack per (X amount of "steps") up to a maximum of 5 stacks. Each stack gives (name of the champions) 10% increase in movement speed.
Thunderbolt (Q Ability): (name of the campion) zaps an enemy with a powerfull bolt of lightning. Deals X (+0.5 per ability power). If it kill an enemy champion, it can be casted again in the following 4 seconds without cost/cooldown. Consumes a stack of charge and has a 800 range. 3 sec cooldown.
Stasis Shield (W Ability):
Passive: (name of the champion) manipulates charge to create a stasis shield that raises his armor and magic resistance by 5% per stack of charge.
Active: (name of champion) unleashes charge to damage and stun nearby enemies in certain range. Enemies in a range of 150 (+20 per charge stack) are stunned for 2 seconds and recieve X damage (+0.25 per ability power). All charges at depleted when using this skill. 2 seconds cooldown.
Charge Blast (E Ability)t: After a short lapse, (name of the champion) unleashes a huge blast of energy in a cone in front of him dealing heavy damage and slowing enemies hit. After a 0.5 delay, (name of the champion) deals X (+1 per ability power) damage to all enemies inside a 750 range 60º angle, as well as slowing them by 20% for 5 seconds. This ability consumes 5 stacks of charge and has a 25 second cooldown.
Generator Module (R Ability)
Passive: Reduce the amount of "steps" (name of the campion) need to create charge by X amount.
Active: When out of charge stacks, (name of the champion) can use his generator to fully replenish it's charge stack. When this skill is used, all other skills have their cooldown reduced to 0. Cooldown: 80/70/60.
Note: This champion does not use MP. Only stacks of charge.
Charge (Innate): It a double-edged weapon. While the way it charges up and the effect it gives can be pretty useful when ganking, it may appear as a huge drawback when you face a teamfight or a long 1 v 1.
Thunderbolt (Q Ability): It is the main skill you're going to use to harass or end champions. Due to it's low cooldown and fairly low cost, it will make you able to use a hit-n'-run strategy when harassing enemies near turrets.
Stasis Shield (W Ability): The passive effect of this skill is pretty useful, since you will be needing to gather charge all the time, stacking extra-effects per charge (specially when they are survival related) seems rather good (yet, still balanced). It's active is great for ganking as well as laning, just appearing on your foes at the high speed given by our innate + the defense buffs and unleashing a devastating stun on them is a great way to start a battle (Still, it depletes charge, so you will have to choose whether to stun your enemies or deal a nice amount of damage to them).
Charge Blast (E Ability): A skill that is useful for harassing and protecting yourself. It's high damage and slow effect will be extremely useful when facing a teamfight so that your allies can rush over and finish them. It's same effects will be useful when trapped in a 3 v 1, or 2 v 1 situation where you can make use the nuke as a way to deter your enemies from getting close, and if they get too close, lower their health and slow them down to quickly leave the spot and let your allies bring them down. It is mainly a support skill, with some offensive/solo potential (depending on your AP).Remeber that by using your ultimate right after spamming this skill you can easily deal massive damage to your foes.
Generator Module (R Ability). It is focused on making you more durable on teamfights and ganks. Raising the rate at which you stack charge as well as giving you an "emergency button" if you see yourself depleted of energy.
Sorry for crappy english, it is not my native language. I hope to recieve some feedback :D