"If the user later decides to cancel their PayPal subscription, it will automatically remove the role as well (unless you charge in arrears you may have to manually give them access for the remainder of the time they've already paid for, something I've only just thought of)."

How are you keeping tracking of the time left? Are you just checking paypal for the time of signup and using ubercart to set role expiration based on that (I also wish role expiration was something you can just type in the date instead of putting in + or - days/month/year). I wish we would only need to use one thing and not have to go back and forth to make things work.

BTW-have you tried ecommerce?