Not about trappings, but more commentary on the thread title.

There is a roleplaying game called Cold City, made by Contested Ground Studios.

http://www.contestedground.co.uk/coldprev.html

Set in post war Berlin, it is about investigating and combating the (paranormal) Things left behind by the Nazis.

Ideally, there will be PCs from each of four main nations - Britain, France, the USA and the USSR.

As you can imagine, these characters will not necesscerily get on.

The game trys to set up a web of competing goals that ideally lead to a situation where you can never be quite sure if you can trust your fellow investigators.

PCs have two agendas - National and Personal. National agendas are handed down from on high, and represent what a sponsor nation wants out of the agency the PCs work for. Examples include:-

++++Britain
Find out more about the twisted technology and possibly use it to provide a secure, new energy source for Britain.
Finish the work of the RPA as quickly as possible in order to save money that could be better spent on re-building the war-torn economy.

France
Prevent any strange creatures escaping from Berlin and potentially making their way across the border to France.
Find a way to use the twisted technology to take revenge on Germany for the horrors of the war.

Germany
Destroy all traces of the twisted technology and the creatures it created in order to prevent any further blackening of the reputation of Germany.
Kill all the monsters in Berlin and beyond to prevent the German public ever finding out what happened.

USA
Report back to the CIA all of the activities of the USSR in relation to the RPA and attempt to disrupt Soviet investigative activities.
Find out the location of the technology acquired by the Soviets.

USSR
Report back to the secret police all the activities of the Americans and British in relation to the RPA.
Find technologies specifically related to modifying the human form in an effort to create a new breed of Red Army super soldier.++++

Personal agendas are what the PC themselves want. Examples include making a fortune out of selling twisted technology on the black market, or defecting to the other side.

I feel there could be material here for a Deathwatch game. Try to give everyone orders from their home chapter beyond 'serve the Deathwatch to the best of your abilities'. These could be something like 'use your position to find out what the Storm Wardens are up to in the Jericho Reach', or 'buddy up to an Inquisitor and feed back information about their activities and ideology to the home chapter' or 'Secure relics for the home chapter' or 'Collect samples from as many alien races as possible'.

And try to encourage players to set personal goals for their characters - be the most Glorious Marine in the Kill Team, or collect material for a paper on Small Unit Tactics or even get posted to a nice safe non-combat billet back on the home world.

(I remember fondly a Star Wars game where I was informed by the GM before the game that my character was actually working for Internal Security, and that it was suspected that there was a traitor in the rebel cell (PC group). I spent the whole one off watching the other characters for sign of duplicity, and when I thought I had them, I revealed myself. 'Hands up, I'm IntSec!'. 'So am I' replied the suspect. 'And me' said another PC. 'And me' chimed in a third.

****, I said, as the real traitor blasted off in a shuttle leaving everyone else surrounded by Imps.)

In short, give the PCs an alternative to coming together as a team. Either they will overcome the friction this creates to form an unstoppable warrior brotherhood with their teammates, or they will they will spend all their time plotting behind each others backs. Either is good for the game.