The idea of several smaller games
is a nice one, but if you want to play the marathon game (it does have a certain effect on tactics) then make sure you have set regen times. If you have to be rescued by your team then make sure it isn't impossible to get near the base/regen point.
The field dressing is a good idea, or a sit out time of 10 mins or so, this would allow each player time to fix guns, gas up etc. The rolling game would then need team tactics then to hold key game points.
I suggest having several pre-selected positions that have point values attached, ie home bases for both teams, strategic bunkers overlooking a choke point, the choke point, a trench network, etc etc. Ok you don't have to have all these, but if you occupy them at the turn of every hour, your team gains their point value. This encourages mini-scenarios to get the points as every new hour approaches. Combining it with the usual point per take down and you are getting a game idea together.
As always with these type of things you are relying on everyone to be honest, so it does need to be explained beforehand that wiping etc, just makes the game really tedious, imagine a several hour long game where you couldn't tag anyone out.......SNORE.
Anyway ideas for now..