In the support forum Timothy and I discussed about additional features for Domain Mapping:
For a certain period of time I would like to give Domain Mapping available for Free accounts as a goodie for the first registrations. If I change Domain Mapping to Supporters only I want the earlier signed Free accounts to keep their mapped Domains, which is not possible at the moment.
This request inspired Timothy to add the following ideas:
+ One off level payment options - Pay once, on there for life.
+ Allow Domain Mapping to be given as an option on a level basis and not just if its a pro site.
+ Allow a fall back level which would be given permanent status once a subscription expires.
Free Level (not payment, currently a feature)
Level 1 - Pay once, access for life (includes domain mapping)
Level 2 - Some cool extra features, if don't renew you get put on the Level 1 access for life option.
I agree, that would give us more freedom of choice and business models.