Danball Senki a.k.a Cardboard War Chronicles

Danball Senki is the anime adaptation of the RPG game produced by LEVEL 5. The game is available on both PSP and your mobile phone. The anime takes place in the not so distant future (2050), and the latest game hype is called Little Battles eXperience or LBX for short. It involves battling small robots made of reinforced danball (corrugated fiberboard) by using flip-top, cell phone-like controllers. As the battler improves, they can enter arena style competitions to determine the strongest! However, things are not always that simple. Enter a sinister group who are creating powerful LBX for their owner personal gain.

In the first episode, the young protagonist, Yamano Ban, is given a briefcase by a mysterious woman. Before running off to avoid capture, she tells the boy, "Within this lies both humanity's hope and despair." Inside the case, Ban finds a powerful robot labeled the AX-00. This isn't like other robots, but you'll have to watch the anime to determine why it's been developed.

This series reminds me of a cross between Medabots & Angelic Layer (remember that one). The model robots are more intricate than Medabots. If Bandai were to produce these action figures, they would be a sure hit for boys in the 5 to 15 year-old demographic, and that is the range of viewers who would enjoy this anime as well.
Official Japanese Site