A few years ago I did a Barbarian class for Swords & Wizardry Appreciation Day - you can check it here. The design behind that class is that a Barbarian could be something other than the traditional "lots of hit points + rage + wilderness warrior". I wanted something more open so I came up with the concept of the "Barbarian" as a class that could react rather than act, besides resisting stuff that would drop other heroes (which is not necessarily more hit points). From that S&W original idea and DCC RPG's lovely tendecy to use random tables I made this Berserker, a class for players who don't like do make plans and who appreciate discovering new abilities every round (if you play 13th Age, this is the same principle behind the Bard's and Fighter's Flexible Attacks).
In fact, others had the idea of a different Barbarian before. If you like to dig for desing ideas, here are some suggestions. I first remember seing a new take on the Barbarian at Kolja Raven Liquette's site Waking Land (for D&D 3rd, you can still check his Berserker class and Savage template here). Basically, Kolja proposed that the Barbarian class for D&D was just an example of a Savage Berseker. You could create Savage Fighters, Clerics or even Wizards. It's a great idea and a better design for a class system IMHO. Other influences are D101's awesome Crypts & Things and Tales From The Fallen Empire.
One last commentary: I like classes that play (mechanically) different at the table. So, if you just want to play a slightly different Warrior or Rogue, I always suggest "reskinning" some abilities or just swapping one or two abilities (I hope to post soon how my DCC RPG's Scout and "Dwarven Tarzan" are). Finally, it's important to mention that lately I've been playing lots of 13th Age and The One Ring, but unfortunately no DCC RPG, so this Berserker isn't playtested yet (and I'm afraid it's a bit overpowered).
Here's the Berserker.