Microsoft has begun to implement such in "Digital Ink" in the latest versions of Office. There are MANY requirements for it to work, such as all being on Windows 2000 and up, an Exchange Server and more.
Frankly, in the states, I see an issue that such can't be legal for use in publicly traded companies. Enron types would have killed for this app.
About the best I've done for somewhat secure content is a PDF with the settings to disallow printing and copying and set the password. But that doesn't stop a "screen copy" feature.
In short, no.
I would like to send a confidential e-mail message but I would like to keep the recipiant from forwarding it to anyone else. Ideally, I would like to make it a message that dletes itself after it is read but perhaps that is a bit too Jim Phelps.
Anyway, is there a way to send an e-mail and prevent it from being copied or forwrded?