With the projector mounted on the ceiling aren't you going to get someone to run outlet to the ceiling?
I'd go up through the wall and if you have an attic right above great it will make it easier. I have seen wireless vga around, but you would still need to plug it in and I am not sure how good it is. (relating to interference)
I might be wrong but I am pretty sure all the inputs on a Hauppauge are going in no video out. You can use your video cards svideo to output video to the tvs.