Well I'm in the same boat and my wife finally agreed that we will be getting an FJ.
I took her for a test drive in the TT edition and she liked it.
I mentioned something about a blind spot and she said that she liked the way the mirrors were very long vertically and she could almost see the curb when turning a sharp corner.
Her only complaint was she liked the other flashy colors more... and she's getting sick of me talking about it, reading forums about it, watching youtube about it, blah, blah, blah.
Right now we're in the saving up stage

(gonna throw a chunk down on it to keep the payments low)
Show your lady your excitement, include her in the test drive, get her to drive it, and she may just suck it up and let you buy it simply because you love it so much
Never hurts to tell her how sexy she looks in it either
Good luck my man,
B