I'm planning on fiddling around with Deathwatch in a way similar to what I did with Dark Heresy, and figure that the part of Deathwatch that's most important is the combat. Since playtesting will probably be individual fights, I need some awesome ideas. Other people could probably benefit from this as well.
I've got one to start us off:
The Flying Menace: In the midst of a late-phase Tyranid invasion, a Harridan creature circles the battlefield from above, serving as a transport for hordes of Gargoyles and obliterating allied armour with it's acidic bio-cannons. The kill-team must drop onto the massive creature's back and attack various weak points while fighting off Gargoyles. Once the beast is dead, the kill-team will freefall to the planet's surface to begin the mission proper.