This is something I had wanted to do a few times also but have never actually tried to implement it. I have had a few ideas though. One idea is to create a new template that has an xform property and a hardcoded file upload control, the xform could do its own thing and the file upload could be handled by the template. This would mean there would always be the file upload on the template but then you could also add a checkbox property to allow users to enable/disable. The other idea which a lot more simplistic is to make the file upload a second step. So after the user completes the xform they redirect to a file upload page. Just some thoughts, but agree it would be a nice to have in the standard functionality. Cheers, Jeremy.