How many units of digital video recorders (DVR) have been and will be
sold for closed-circuit TV applications (security and non-security) in
the US and rest of the world for 2003-2008? I'd like sales quantities
for each year. More detail is better!

Not sure if you will be able to find the answer on that one, as you
are asking for projections.  What I can tell you, is the number of DVR
CCTV recording units has been exponentially increasing every year! 
And this trend will continue, as VCR based systems are completely
obsolete as they are excessively cumbersome, require too much user
interaction (changing tapes, pressing record) etc.

   The question you have posed also leaves much open...such as
differences between Standalone DVR Units and PC-Based DVR Units.

Good Luck finding the answer you are looking for.

Michael
Ez-Toyz Inc.
http://www.ez-toyz.com