I'm wondering with all that we've heard strongly rumoured about the car if Nissan are just throwing all their eggs into the Le Mans basket. Mike Fuller reckons that a 15-20% drag reduction on a traditional LMP1 design is possible with what Nissan have done, but that ultimately comes at the cost of downforce. This approach effectively rules Nissan out of being competitive at any other circuit in the WEC calendar, which are all fairly typical purpose-built circuits that require the big downforce numbers to be competitive on.
Add that to the rumours of big horsepower from the combined ICE-Hybrid system and it all points to a Mulsanne-eater. If the hybrid system is designed to be deployed for the amount of time they expect to be at full throttle on the Le Mans straights, they may have something going... they'll suffer in the Porsche curves and in the few other normal corners like the Dunlop curves and Indianapolis but could make it up for it on the straights.
There's still a part of me that thinks they'll end up rolling out a fairly normal looking P1 car that has some interesting advances in the hybrid system (that horsepower figure is too tempting not to ignore, Toyota were getting 1000bhp total last season and their hybrid system wasn't even in the top megajoule category, so 1500bhp+ doesn't sound too ridiculous to me), but there's too many in-the-know well-connected people saying it's something much more unique...