Just scanned this article in SQL Server Central by Jason Selberg.
It details how to get data driven subscriptions using the Standard Edition of SQL Server.
"Do you have SQL Reports that need to go to different people but each person's report has different parameters? Don't have the resources to purchase the Enterprise edition of SQL 2000? The only solution available in Standard edition, besides writing your own front end in .NET was to create a subscription for each unique report, person and parameter. After only a short amount of time, you've got a ton of subscriptions to manage."
The technique uses a Stored Procedure to manipulate the Subscriptions Table in the Report Server database.
A useful trick to have up the sleeve.