I have somewhat interesting development situation. The client and deployment server are inside a firewall without access to the Subversion server. But the developers are out
svn export
does not accept a revision range, try it out.
A possible solution is to get the list of changed files with:
svn diff --summarize -rXXX http://svn/...
and then export each of them.
You could try playing around with the svnadmin dump command that ships with the Subversion binaries. You can use this command to dump the whole repository to a file, just certain revision, or a range of revisions. Then use svnadmin load to load the dump-file into a new, clean repository.
Not a perfect solution since it works in terms of the repository and not individual files.