I would like to add a file to a remote svn repository without checking out the project.
svn add requires the project to be checked out
svn add
sv
This might not be what you are looking for but you can use -N flag to checkout a code non-recursively.
Example:
svn co -N http://svn.example.com/repo/trunk
This will not checkout all the sub-directories. Which is much faster if you are just trying to add a file.