Manual usergroup promotions with expiration date?

[Tourmeister]

Howdy,

I REALLY need the ability to promote certain users to a usergroup manually but also have an expiration date for their membership in that usergroup. There does not seem to be a convenient way to use the subscription service to do this without charging money.

It would also be very nice if an email were generated and sent to both the user and me notifying us of the impending expiration (say a week in advance) and then another email once the expiration actually occurs.

Any suggestions or ideas?