Yeah that is indeed true, but the main panel and screens will be I bet. Most of us simmers will already have a form of flight yoke or joystick. That throttle quadrant appears to be one from a company like "flight deck soloutions" which cost a fortune :(
Here is a good example of a home cockpit. this would probably cost less than 2 iPads! I plan to make my own very soon, I really want to get immersed into the environment of fsx. I like your idea about using PMDG's poster or a similar method.
It would be much cheaper to buy LCD screens than Ipads. You can also only display things from fsx on an iPad through an internet connection, so it would be sluggish at times. You would benefit from LCD screens as they connect directly to your pc.