You sound like you love your wife. Consider that the resentment may not be targeted at her exactly but more toward the situation that has grown worse over the years, for whatever reason. Try not to place the blame on anyone in particular, sometimes life just gets in the way.
Patience is key. You're right, bit by bit, encounter after encounter can help her feel more and more comfortable. However what's really going to help her be more open is you. You've got to figure out what pushes her buttons, and most of all figure out what really turns her on.
If you can get her turned on, and I mean white hot, it may take some work on your part, but boy will it be worth it. It all depends on how much you're willing to invest. Sexuality and passion has to reach outside the bedroom, and gravitate away from the genitals to get the type of passion your looking for. That I don't care who sees us, I have to have you now, type passion. It's going to have to appeal to her brain, and you want he to be at work or at the supermarket, thinking about making love to you.
First thing is opening the lines of communications (patience), simply talk about sex more. Tell her what you like about her body, the nape of her neck, her breasts, her scent, her eyes. Ask her what her fantasies are, what would she like to do that she's never done, and then make it happen for her. Buy a sensual book (not sex book) but something that has tasteful nudes of men and women, something you can give her as a gift.
Try giving her a massage....full body, nothing but a towel, candles, music, wine, the works, whatever you know she likes. You can use a bristle hair brush and brush her body from her neck to her toes, and after use hot oil (sit in a sink of hot water) to give her a massage. Make her feel good without expecting anything back from her, even if it means letting her fall asleep and kissing her on her forehead.
Order some catalogs on sex toys, and look at them in the bed together and see what interests her and order it. Leave sexy and sweet notes for her in the least likely places. Call her in the middle of the day just to tell her you're thinking about her. You can get thousands of ideas for romantic idea by simply googling 'romantic ideas'.
I it has to be a tent, then let it be a tent. You can move on from there. If you're not showing your faces in the pictures, then don't worry about it. Why don't you offer her to take your pictures first. Or the two of you can take pictures while having sex. Let her keep the camera or hold the pictures until she feels comfortable. If she never wants to post them, don't push, if you can get her to even take the pics that will be a first step.
You may be right about the truck driver one, maybe I watch too many horror movies. (smile)
I don't consider these thoughts too over the top or deviant, although I know there are people that would. She may not consider them right now, but in time she may trust you enough and feel passionate enough to be willing to compromise.
I hope this helps