Can't find any product that will let you.
Did a search on DX and google.
It's possible though. Read a document saying you could just straight up run an cable from your ds to the tv, but it would be hardmodded, and if you ever wanted to take your ds with you, the cable would be dangling about which would be terribly unruly.
There's also the other means of doing it is the projector device you were talking about that is clunky, uses mirrors, and only displays one screen.
Hope you find out the solution, but I always wondered the point of this, because doesn't this defeat the purpose of a handheld? I mean, it's supposed to be portable, and you end up grounding yourself to a tv just like any other console.