Okay, serious now.
Accurately reproducing the feel of Starship Troopers (nearly any of them) is going to require some work with L4D.
First, as Heinlein stated, if you trade 100 Bugs for 1 human soldier, it's a net win for the Bugs. The simplest way to accomplish this is to dumb down the individual threat of your enemies and add lots more of them for the proper feel. Of course, this induces lag.
Second: You will be cruificed if you don't include the power armor (if nobody steps up to do it themselves, I will). Novel Marauder suits would be nice but we don't know anything about them. Terran Ascendancy Marauders are better documented and we have a good idea of their capablities; there are also different suit types like the Command, Engineering, and Scout suits in Terran Ascendancy, and there are different classes of such suits, so the L4D theme of different players with different abilities can be maintained (though a visual redesign for some of the more nonsensical Matrix APU-like types would be recommended). Roughnecks had the standard Power Suits and the heavier Marauders; Power Suits are closer to the novel's feel but light on the firepower, Marauders are large, heavily armed and armored and nearly impossible for Bugs to destroy as long as they still have power. Cap Troops from the movies are ridiculously lightly armed and squishy; movie Marauders are apparently just not something the Bugs can actually deal with.
The overall recommendation then is that you adopt the Terran Ascendancy model. In the Terran Ascendancy mode, a Class-1 Marauder (kills targets) backed by an Engineering Suit (not very tough and crappily armed, but he'll save your life and your suit), a Class-1 Command Suit (Power Shield so he can stick himself out front and absorb damage while the others gun down targets, or do some reasonable gunning down of his own), and a Class-1 Scout Suit (some form of suitable recon device like a tiny UAV and reasonable gunning down ability) would make an ideal team and fit in with the L4D ethos of four players with disseperate abilities. Having players be able to access lesser suit Class at the start and unlockable heavier ones would play to the console unlockables mania.
That just leaves the minor matter of incorporating "on the bounce" to deal with. How such a thing as jumpjets would be done is left as an exercise to the Kalfireth.
Third: L4D can't handle the level of firepower any of the Starship Troopers settings bring to the field. Handheld flamethrowers, grenade launchers, miniaturized nuclear weapons. You can probably just smile and nod, like many modern games do about having the ability to rearrange the landscaping, but still.
