WordPress pay per post model & integration

We're turning our attention to aMember again in the hope that we can achieve our aims with our project, which is: to use aMember to control access to WordPress so that we can charge and register members (authors), so that they can create listings (posts).

Most WP membership sites I've seen, it seems, use aMember to charge people to view special content, or in the case of some of the big theme shops they use aMember to control access to an area where people can download plugins or themes.

We plan to use WordPress as a listings directory whereby members join and list their properties.

The idea is they sign up using aMember which will then login them into an account area where they can perform the following tasks:

- Create a profile in WordPress.
- Edit certain fields in their WordPress user profile, i.e. add/change photo and other details but not change the date their joined.
- View and print invoices.
- Create a post (as this is what they paid for).
- View a list of their posts.
- Edit their posts, via a link to their posts.
- Buy more posts as and when they wish, i.e. buy the ability to create a post for a predetermined fee.

I realise some of these features are present in aMember and some will probably need to be customised to suit our business idea.

All of this functionality is can be achieved using the Classipress WordPress theme by AppThemes.com but their solution is intrinsically flawed as a listing site and too inflexible and
for that reason we are not too keen on using their products, and besides, their support isn't very good overall.

So, we are trying to build our site exactly how we want it and how we think it should be.

We would love to be able to use aMember to handle the business process as we feel it is a mature and great product plus it has a good support system.

Any insight as to whether we are on the right path with our idea would be deeply appreciated, thanks.