Look into vinyl wraps. They could be the solution you need.
Change your preferences or buy Toyota. 
I told my salesman I wasn’t trading in my almost-paid-off Corolla for the new hatchback unless they got me the Blue Flame color and 1% APR, or it didn’t make sense for me. He managed to grab one off the cargo ship, and I had it six weeks later—plus the 1% APR.
So technically, it was easy, but I think I got lucky.
@Marcell
That wasn’t a custom order. It was just a car that was already allocated. Also, the salesman doesn’t decide your interest rate, the bank does.
A full respray is going to be expensive, and it’ll likely cause some damage or defects during the process. The car might look different, but it probably won’t be in as good condition as before. From a resale perspective, a full repaint would also hurt the car’s value.
At that point, it might be better to just buy the Highlander, since the extra cost would probably be similar to the cost of a respray and the hit to resale value.
If you’re willing to spend a lot, check out Porsche’s Paint to Sample Plus program. It’s only $22,860. 
I know this isn’t what you want to hear, but learning to like one of the offered colors will be a lot cheaper and easier. I love the new Ocean Gem color on the Camry, but not enough to trade in my current one or deal with wrapping it. Once the car feels like ‘yours,’ the color will grow on you.
If the color you want isn’t available, it’s not going to happen. A decent respray will run you about $8k.
It’s not going to happen unless you wrap it.
You can get the car you want, or the color you want, but not both. Custom options aren’t available.
I just got a Cypress Green Hybrid Platinum Highlander with Caramel interior, and it’s perfect for my husband and me. It’s not too big—great for golfing and traveling. I’d recommend test driving one before ruling it out as ‘too much car.’
@Bradas
Haha, that’s the exact setup I was looking at! But my Highlander build was $56k compared to the $44k RAV4, so size isn’t the only factor. I also haul things for work, and my colleagues manage fine with RAV4s, so I’m leaning that way. But I keep my cars for a long time, so having something that could accommodate a growing family is appealing. I’ll definitely test drive the Highlander just to be sure!
@Jaime
Once you test drive a Platinum Highlander, you won’t want the RAV4 anymore! I also keep my cars for 10+ years, and I bought the Highlander for that exact reason. If you like it, get on a waiting list ASAP—it took me 1.5 years to get mine in the color I wanted. Happy to answer any questions or send photos if you’re interested!
If Toyota doesn’t offer the color, your best option might be to buy a white one and have it repainted.
Indra said:
If Toyota doesn’t offer the color, your best option might be to buy a white one and have it repainted.
It doesn’t matter if you buy white, black, or any other color—it’ll still need to be sanded down for a full repaint. Maybe you could skip the engine bay and door jambs, but a full paint job on a new car could run over $20k if you want it done right. If you just paint the exterior, it’ll probably cost closer to half that, but you’re still looking at a big expense.
@Cass
White is just the easiest color to find in stock. And yeah, wraps aren’t ideal in hot areas. Painting it once is better than having to rewrap it every year.