I haven't heard these rumours, and to be honest, I usually hear rumours like that pretty quickly, because I follow a lot of good sources of rumour-y information, particularly for nerd media stuff.
Still, it'd be good if true. There's a ton of fantasy on TV these days (albeit most of the "warped fairy tale" variety), and if a D&D show had the right writers and cast, and a plot and tone that was accessible, it could have legs, but god, it would be so easy for it to go wrong, and there are so many showrunners out there who would love the idea but make a horrible mess of it.