According to http://en.wikipedia.org/wiki/Wikipedia:Size_of_Wikipedia#Hard_copy_size, if you printed it in volumes 25cm tall and 5cm thick, it would take up 1448 volumes.
ETA: more details of the calculation at http://en.wikipedia.org/wiki/Wikipedia:Size_in_volumes.
If you measured the font in microns.
Of course, the problem is, that before you’d finished printing the first volume, it would already be out of date.
This is an blog post about a guy who actually printed and bound all of the edits to the Wikipedia article about the Iraq war made between December 2004 and November 2009. Admittedly, this is a large article, but the 12,000 changes amounted to 7,000 pages or twelve volumes.