Just run this code from inside your repository. This will do a bulk action like "svn add" on each file marked with the given filter (like '?') when doing "svn status"

Beware: this code might break with multi word filenames...

usage :
# ./svn_bulk ? add ---> this shows a preview of the actions
# ./svn_bulk ? add 1 ---> action !

#!/usr/bin/ruby
sign, action, doit = ARGV
sign = '\?' if sign == '?'
list = IO.popen("svn st")
list.each {|i|
if (i =~ /^#{sign}\s*(.*)/) 
cmd = "svn #{action} '"+$1+"'"
print cmd + "\n"
system(cmd) if doit
end
}

Taken and slightly adapted from www.robgonda.com/blog

svnadmin dump /path/to/repos > proj.dump
cat proj.dump | svndumpfilter exclude somefolder > cleanproj.dump
STOP SVN services
BACKUP /path/to/repos/conf /path/to/repos/hooks (all custom configuration for this repository)
DELETE /path/to/repos
svnadmin create /path/to/repos
RESTORE /path/to/repos/conf /path/to/repos/hooks
svnadmin load /path/to/repos < cleanproj.dump
RESTART SVN services