Ability to change the user WPM uses to run the transaction

I've come across a situation where we need to have a cert to access an internal SharePoint site. This cert is tied to the users account and their machine. It cannot be exported what so ever. If we had the ability to tell WPM to use another account to run its transactions we could easily set up a domain service account to be used with these certs on designated stations to run our tests. I'm sure other users would like more control over what users get created on their machines and what they are doing.