The Yakuza 4 "Kuro" and "Shiro" editions are exclusive to the UK and Australia, respectively, but you needn't despair if you're in North America and you want the bonus DLC. Sega announced today that all the downloadable extras from those editions will be included with every new copy of the game here. That includes the Fighting Arena, Survival, and underground car park racing modes, and costumes for all four playable characters (and for Kazuma's daughter Haruka too). In addition, pre-ordering from GameStop will give you yet another downloadable bonus: a hostess-themed dynamic theme for the XMB, which is sure to be humiliating.
The only thing missing from those limited editions, then, is the fancy steelbook casing. If that's what you wanted, we suppose you can get back to despairing.