I know this is not actually the question you ask, but.. not the range?
Have you looked at the NeoNate 6500D? It has a range of 800m (thats 2650ft in freedom units). I know you have big houses in the US but..
Edit: Didnt see the video part, sorry. I wont have any of the online models in my house
Edit2: Seems like Neonate has a video model with 300m range (approx 950ft). Dont known if thats enough. Anyway I can vouch for the brand, super babymonitors. Think its the most commonly used in Denmark