You can retrieve Quicktime files manually from /tmp/501/TemporaryItems/ (assuming 501 is your user id number) while the browser is open. The name will be something like QTPluginTemp387308. Just move it to the desktop and rename it to mymovie.mov and you're all set.
With Flash, I usually use something like the command-line app curl to get those, and hope they are not smart enough to use LoadMovie().