Email subscriptions: changing "from" address for different subscriptions on same s

I doubt this is possible, but can someone think of a way to change the email address used for sending report subscriptions based on the report or subscription?

It's a need that I've heard from a number of different clients. Scenario: a company has one reporting services server with reports running from numerous departments. Report subscriptions are sent to internal and external email addresses and there's a business need to use different "from" addresses based on the report (or audience).

Unfortunately this isn't really possible without doing some messing around. You can make a call to the RS WMI provider to change the SenderEmailAddress value, but you would have to synchronize the code making the WMI calls with the subscription times. Definitely a hack :-(.