It's not Vegas, but these slots will take your money.
NCSoft / ArenaNet announced that, starting this summer, alternate character slots for subscription-free MMO Guild Wars may be purchased for $9.99 / Â8.99 / Â£5.99 a piece. This is a one-time fee. From GamesIndustry.biz:
As a result, NCsoft presumably believes the facility will enjoy a broader appeal than it would for traditional massively-multiplayer games, and that relatively casual players as well as hardcore Guild Wars fans will find the chance to play as more alternative characters - while retaining access to other unlocked content - worth the extra fee.
Given that buying the box for $52.99 grants you four character slots, I suppose you could argue that the $9.99 fee gives you a ~$3.25 piecemeal discount. If you love your PvP, this could be a nice way to supplement your collection post-Factions expansion.