Few questions about paid subscriptions

[Cebby]

I have a little different situation.

i know how the Paid Subsc. feature works and use it on a couple of my sites. One thing that would be helpful is the ability for users to make a 1 time donation that will change their usergroup and not expire. Right now as a work around, I just put "30 years" in the duration, but this is confusing to people.

Is there a hack that does this - I haven't found one if there is...