While I really wish they did something like that too, think about it... it's not gonna happen. iTunes Match for Music makes sense because many people bought music in CDs in the past and it is legal to copy those over directly via iTunes. For movies, though, you cannot legally rip DVDs (with a few exceptions) and therefore, if you don't do anything illegal, every movie you have on your computer was bought from somewhere online, and odds are that somewhere was iTunes. In addition to this, I can't even imagine the price of iTunes Match for Movies, considering that it's $24.99 for songs that cost, on average, $0.99. If you consider that a movie costs on average $9.99 (and many cost more), then multiplying the cost of iTunes Match by 10 gives you $249.99, which I don't think anyone would pay...
Pietro