There are graphic clients available, in various stages of maintenance (see the Wiki article on NH). But I keep going back to the text version. It's like porting Pacman to the Quake or other 3d engine - you don't really gain anything, and arguably the visual distractions get in the way, over-emphasizing the limitations of the square grid and limited view. Additionally, the isometric 3d of some ports makes it too easy to step into the wrong square.

When I was in High School (80s) I used to sneak onto the campus of the local technical college to play Hack.

I suspect it would take more than a million dollars to make a modern graphics-rich game, regardless of its basis in Nethack.

I'd certainly like to play such a game, though. The depth of the Nethack world is impressive. Put it on the Wii so I can swing swords, throw daggers, fling spells, etc. and I would probably never be heard from in the real world again.