I am considering SS for a website in which members can log into a certain area -- if they pay their yearly dues. Is there anything built into SS or a known module that could handle this? If not, do you think SS could still handle it with some custom development?
No public available module for such a thing but it has been done http://www.salehoo.com and our SaaS application Dawn (http://silverstripe.com/dawn) does access based on whether you have paid your bills. Most of the code isn't in a nice easy to use module, you will have to assemble some components yourself.
Of course thats a very simplified version but just the general idea. Member Profile module might be too much so you could make your own form in that case. I decent level of PHP knowledge would be required! Good luck
The payment-test module, that is an example of how to use the payment module, does actually register members on the fly when they buy one of the products and email them - I was thinking about doing a paid membership by updating the member row with some additional data about when they registered and depending on what package they bought when their membership would expire.
There are some functions in the payment-test module to support recurring payments with DPS as well but the example in the payment-test module is just for processing one off payments.