For billionaire hedge fund exec Jeffrey Feinberg, that just became a reality ... 'cause the dude just bought a $44 million mansion in Los Angeles -- THAT COMES WITH BOTH!!!

Feinberg just purchased the property recently, the house’s developer, Ramtin Ray Nosrati, told The Wall Street Journal -- and it's one of the most ridiculous places you'll see.

There's 7 bedrooms, 11 bathrooms, it's 54,885 square feet AND it sits on over 1.2 acres of land.

But, the best part of it? It's got a custom Kobe court that would make NBA arenas jealous.

Check out pics of the place ... it's got Kobe's signature, his jersey numbers and his famous Mamba logo emblazoned on it.

There's also pictures of NBA legends like Michael Jordan and LeBron James surrounding it -- and Feinberg, a huge basketball fan, actually told the WSJ it was a key reason he bought the place.

As for the rest of the crib ... it's got it all -- a room devoted to a golf simulator, an indoor pool and spa, a bar and so much more.