Honda announced that the 2014 Odyssey will offer a built in vacuum called HondaVAC. While a good concept, it will only be in the $45K Touring Elite version of the van - the one that well-heeled senior citizens buy, not middle class families shuttling kids with baggies of Cheerios. Also, if you want to really impress us, equip the van with a Roomba type device that automatically cleans the interior while the van is parked.
I don't think it's a good idea to have a built in vacuum in a car. There are too many driving distractions now. People would think of too many wierd things to do with a vacuum that could suck the chrome off of a trailer hitch.