Too expensive for my tastes (the pricing for the Cintiq seems to be at least partially "we're the only ones with something like this on the market so we can charge whatever we want").
Well, it looks like it is possible to build DIY Cintig from a LCD panel a normal Wacom panel (with a bit of skill
There is an example buildlog:
An there is a forum of the DIY Cintiq community:
So I am now hunting for 15" LCDs with external power supply and old 12"x12" Wacom tablets