This is an Automator script to generate spam report emails utilizing some AppleScript code. Open it with Automator, change the recipient address, install it as a service, and set a keyboard short-cut (I use fn+ctl+alt+command+S).

send_to_spam_via_applescript.zip

This is an Automator Service that sends the full source of a selected Mail message to the address of your choice (like spam@myISP.foo).

Open it in Automator, edit the recipient address in the new message step, then after saving, copy it to your ~/Library/Services folder.

Here is the file: Send to Spam

To make the process less dangerous, I removed the message send and message deletion short-cuts at the end of the workflow. To re-instate them, simply run a “follow-me” for Shift+Command+D to send, and another for Command+Delete to delete the selected message.