While I found Dead Island interesting, I was much more impressed with Warhound, a sort of uber first-person shooter that's built around the concept of mercenaries. In the Xbox 360 and PC game you select missions then build out your kit and get yourself to the drop zone on your own dime.
The developers even created a hideaway for you to store your weapons, train and, perhaps, customise your home.
The start-up menu has you log in to a fictional database to find what missions are available. Then you hop to a map which pin-points your target's location and gives you a variety of drop points, each with its own cost. So having a boat drop you off on the shoreline far from your target might cost you $500 while having a helicopter drop you off in the middle of the jungle much closer to your target might allow you by-pass some of the bad guys but could set you back $9000. The bottom of the same map also shows your timeframe, often a three day spread, with weather predictions for each hour of each day. You get to decide what day and time you want to drop in, but if you wait to long there's always the chance that another mercenary drops in and lands the target before you do.