I've built 4 houses and have used all the products mentioned but vinyl. Vinyl sounds good in theory and a few homes around here had it up until 2 years when we had a rare but massive hail storm. Wish I would of taken picts

It looked like someone threw baseballs at the sides of houses. Huge holes everywhere. Even though hail storms are rare here it's to risky after seeing that.
So on to what I have used. I've used the product Mtmuley mentioned called Canexel. It is very similar to LP Smartside products. They quit carrying it around here but there are 1000's of houses with them installed. It's a very good product.
My current home has Hardy lap siding on it and I have those cedar gables your wife likes.

I also have hardy panels in the gables for a board and batten look.
The research I've seen is that no matter what product you choose I would go with a factory color. The houses around here that have painted there hardy or Lp products look like crap in 5 years, especially the south sides. They fade real bad. It might be cheap exterior paint but I doubt they all used cheap stuff.
The factory paint like you said is almost baked on and hardy has like some titanium in there paint.. So if you're thinking of saving some money and only buying pre primed hardy or Lp and painting it yourself, I would say Don't.
I build and sell every 2 years so I can't give you longevity of the products but I do run my mowers around 100's of houses and notice how things are holding up. Kind of nerdy I know.
I think if I had to pick I would go with the Lp smartside product in a prefinished color. The reason is that even though hardy has their own finishes I have seen them deteriorate with moisture. You really can notice it around the High Efficiency furnace pipes coming our the sides of the house. The air is hot and moist and that combo has the hardy peeling.
All in all if you can keep your sprinklers from hitting the house and you use any of the above mentioned products (pre finished) you'll be happy.