I work at a local Nissan dealer and my first vehicle was a Nissan, I love thier cars and trucks! The Titan and the Frontier are both great trucks. The Titan has torque out the ass and most of the problems have been worked out. Yes, the first few years of production there were problems. The read end was overheating to quickly and giving out with the torque and the brakes were too small. Also the king cabs had problems with the air bag wiring causing them to fail. Nissan adressed all the problems and still continues to adress them. The last gen frontiers had a dog of an engine in my opinion, the 3.3l dosn't seem too good on gas or power but the new 4.0 is a beast. The Frontiers handle and accelerate like a sports car! In fact, I'm looking at both of those trucks for a future vehicle.
I'm still a huge Ford fan and would love to own an F150 as well. I currently have my ranger but with my girlfriends 2 kids, my truck just dosn't work. I don't like having to borrow my brothers car if I gotta pick the kids up from daycare and school. Yes, an extended cab Ranger might be nice but, the only problem is the back seats are as pointless as tits on a bore, especially with 2 small kids who need a booster seat and a car seat.
Both companies have great designs, the new Maxima is a beast on the road from the 20 miles I drove one. That car will accellerate faster than you can hit the gas. The Z's handle like they are on rails. The engines (VQ series) have been one of Wards or C&D's (I'm not too sure) 10 best engines for almost 10 years. The new VQ37 (370Z and G37) dosn't have any cams! It's all actuators in order to deliver more precise control on the air fuel mixture.
The only thing I can see coming from Ford and Nissan would be the next gen Titan. Nissan would be wise to do so, it'll keep production running high for Ford and Nissan would be able to bring over the Commercial Vehicles they've been wanting to. This would be a win/win situation for both companies. Ford could also use some of Nissan's technology from the commercial vehicles they've got like the desiels. This would have been almost the same set up as the failed Dodge/Nissan alliance. Nissan could also work closely with Ford on the next gen Frontier Ranger/F100.
But, in the end, this is all speculation. We can't say anything untill we hear this from the horses mouth at both Ford and Nissan.