S3 extension with multiple accounts

Is it possible to get the S3 extension to be able to use/choose between more than one AWS user? I like the current form and it accomplishes most of my needs but it would be more useful for it to have access to more than one account.

Not currently; that information is configured at an extension level.

We do have a feature on the backlog that would allow for multiple extension configuration profiles, but that's not schedule for a specific release yet.

In the mean time, your best bet would be to modify the extension (we can provide source code) to bring these peroperties to the action-level.