I have a use case where I would like an add-on or admin to set a users group with additional privileges and provide an expiration that would change the user back to their original group, or even a default group such as members.
The goal would be to allow members to purchase a "subscription" but not as recurring.
I assume this can be done with simple commerce, however from everything i have seen there is no way to allow and administrator to change or setup and expiration for teh group change. Adding a transaction manually through Simple Commerce does not act as a subscription, and thus teh group change features will not work as intended.