The Elder Wand was unique, especially due to its long history.
The Elder Wand wasn’t simply a wand made from elder wood and thestral hair - it was a wand that “learned” from many masters since the Middle Ages.
“Believers in the Elder Wand, however, hold that because of the way in which it has always passed allegiance between owners — the next master overcoming the first, usually by killing him — the Elder Wand has never been destroyed or buried, but has survived to accumulate wisdom, strength, and power far beyond the ordinary.”
- The Tales of Beedle the Bard
This sort of history spanning centuries would be impossible to duplicate in any reasonable time frame, even with a new wand made with the same type and quality materials by a wizard equally as powerful as the Peverell brothers.
However, at least one wandmaker, Gregorovitch, did study the Elder Wand and possibly tried to duplicate it.
“It was a rumour,’ whispered Ollivander. ‘A rumour, years and years ago, long before you were born! I believe Gregorovitch himself started it. You can see how good it would be for business: that he was studying, and duplicating, the qualities of the Elder Wand!”
- Harry Potter and the Deathly Hallows, Chapter 24 (The Wandmaker)
Even if he did find out what it was made of, though, he couldn’t make a wand that would be immediately as powerful as the Elder Wand. Theoretically, it might become as powerful as the Elder Wand - but it’d take a while.
It should be possible to make a wand that’d in time be equally powerful.
The Elder Wand doesn’t have any components that can’t be recreated. Presuming that Dumbledore was right (since he usually is) and the Elder Wand was made by one of the Peverell brothers, not Death, there’s no reason creating a wand that eventually becomes as powerful as it should be at least possible. The talent of the wandmaker might have a part in how powerful the wand can become - the Peverell brothers were said to be extraordinarily talented wizards, so that might have been a factor. However, if a skilled wandmaker makes a wand with the same specifications as the Elder Wand, and it’s passed along for centuries, it should theoretically be as powerful as the Elder Wand. Perhaps the most difficult part would be getting wizards to pass it on into the centuries, since there’d be no legends behind this new wand, and wizards generally tend to prefer their own.