You can try some of the people mentioned on this (old/outdated/no longer updated) thread to see if they still have tinamou or know someone who does:
Softbillsforsale may have some occasionally, but definitely not often. I would search the forums here too as someone had contact with someone breeding chileans. Do not post a wanted ad on there...all I've ever gotten were obvious scam replies.
The elegant-crested tinamou we had at the aviary had two common problems. 1. They are prone to stress. They fly straight up when frightened and can scalp themselves, but we also had some simply die from shock/stress, like rabbits will. One night, we lost two birds simply because a predator had been snooping around their cage. That fright was enough to kill them. 2. They are not cold hardy. I can't remember the exact lock in temperatures we had for them, but you have to actively lock them in when temperatures drop. They are not genius birds by any mean, so won't go in on their own.
You'll probably have to do a lot of digging to find anyone raising them. They are pretty in private collections!