By my count the US constitution has 7 Articles and contains around 4600 words in total (including words such as Article AA, Section SS Clause CC but excluding title and the names of the signers) fitting on roughly 10 pages when nicely laid out. Admittedly the various ratified amendments add a bit to this but even adding them it is hard to do more than double the total size.
The proposed EU constitution has a Preamble, Four Parts and a Final Act but just its table of contents alone contains nearly 2000 words and occupies roughly half the amout of space as the entire US constitution. The entire constitution is 485 pages which contains just under 160,000 words.
Is it any wonder that people say they haven't read it?