It's already been done for Counter-Strike, so why not for Warcraft? A team of homebrew devs came together and brought us Warcraft 2D PSP - three guesses what it is. Obviously it's not as feature-packed as the real thing, but it's a good start to a 2D portable version of the game. Here are the features as described by the dev notes:
* The game is played in real time, you're a single character
* The game is played in 2D
* You have the choice between 2 teams: Orcs and Humans
* The game is playable online therefore only player against player, an artificial intelligence may be present in a new version
* Different classes of people will surely be added in a new version
* The game is now in English
* A system of experience points and levels is available.
* If the game appeals to many people, developers will be thoroughly inside and create a persistent universe with a server.