"2008 highlander": my guess
Go to the website toyota has and click on future cars, click on future/concept cars, then click on FT-SX. It is the only concept mid-sized suv there, and fits the general description given by the spies. If it's not, that would mean that they have yet a fifth suv in the pipeline - NOT!
Oh and by the way, it is schmarmy on the outside, like the Pacifica and the tribeca had a baby, and the mobile MPV from Ark II was its cousin. The inside is futuristic with respect to Star trek pilot type seats, but I am also guessing that that won't roll out in the actual car. I may think about it because I am guessing that it is going to be longer and wider than its predecessor, but then that would be like marrying a guy (or girl) that is really smart and nice, but boring or revolting even to look at.
Just so you guys put my comments in perspective, I am a barely 40 female professional with two kids, one 5'11 step-daughter, one step-son, and I think that the Infiniti FX is the most beautiful SUV ever made, and the new MDX is a great function/looks compromise. I think the 2005 Rav is the best looking small SUV ever made.
If either of those came in hybrid or had even reasonable mileage, with regular instead of premium gas, I would drop my highlander dreams like that chubby guy from the marching band, while recommending him to my not as cool as me best friend.