@Lazy Badger: Actually the SVN redbean book clearly proscribes that you may edit the dump file for this very reason, with the expected warning that you do so carefully and without changing line terminator characters. In fact, for the example scenario discussed, they cite editing Node-path and Node-copyfrom-path in order to alter the path to which the dump file is restored:
If you want your trunk, tags, and branches directories
to live in the root of your repository, you might wish to edit your dump files, tweaking the Node-path and Node-copyfrom-path headers so that they no longer have that first calc/ path component.
I've done this a number of times when using cvs2svn to dump CVS repos for import into a different SVN structure. I first create the dumpfile and then use sed to modify the Node-path and Node-copyfrom-path headers prior to loading the dump file into SVN. Works fine.
Here's a quick & dirty shell script I use (warning: no error checking, so use at your own risk). The old and new paths must be specified starting from the root node path.
Usage: <script> <dumpfile> <oldpath> <newpath>
#!/bin/bash
echo "Replacing path starting with '$2' with '$3' in file $1..."
sed -ri -e 's@^Node-path: '$2'(/|$)@Node-path: '$3'\1@' -e 's@^Node-copyfrom-path: '$2'(/|$)@Node-copyfrom-path: '$3'\1@' $1