There is a little script here :
http://www.srparish.net/scripts/
it is called chuid. Your host will have to install it but it will allow for file uploads for everyone in safe mode. Afterwords, you'll be able to do something like this :
passthru ("chuid $file 1033");
@copy("$file", "/path/to/uploads/$file_name")
or die ("could not copy file $file_name");
Which 1033 being an example UID. To find your UID in shell you can do this :
echo $CHUID
This is one solution anyways :-)