The MadCatz converter essentially turns the 360's AV port into an HDMI port, as in analog to digital, so it should do exactly what he's trying to do. The thing is, what he's trying to do (as in use HDMI on his non-HDMI system) is essentially pointless, since A. he would need to buy this $100 adapter, and B. convert analog to digital, so it's still really an "analog image". The 360 can output 1080p over component, VGA, and HDMI, so if his projector only takes 1080p over HDMI, then it should work just fine using the MadCatz adapter. That's the whole reason behind this product, unless I'm mistaken. Still though, if he wants true, digital 1080p with his projector, then he'd be better off selling his 360 and buying an HDMI system.
I don't see why you would need 40 feet of video cable, since you get wireless controllers. If it's because you use a wired internet connection, then you'd be better off just buy 50 feet of Cat5 cable.