Mark up? What Mark up?
Pi Model B: £32
10" touchscreen: £50
Camera: £24
SD Card: £5
Case: £5
Total: GBP116, which is USD180 or so at non-apple exchange rates. That's at the economies of scale that most hardware manufacturers could only dream of. Add in the vast quantities of free coverage for the Pi due to articles in the tech and non-tech press, the favourable distribution with Farnel/Newark they no doubt were able to negotiate based on quantity, and the fact that most of their software is written for free by the community.
Now compare to USD200 per unit for this device if you buy three of them.
So I'll need you to clarify where the massive markup is, because I don't see it.