At this time there is no release dates, we do not believe in release dates as it helps instill false hope and development of any project is "floating", placing a date on it makes development difficult putting developers under a lot of stress to meet the deadline. So best release date I can give is "Soon".- Is there even a very rough date for the release of the next updates of CBSubs with the added payment gateway API functionallity?
Not that I am aware, to my knowledge only major gateways will be supported native.- Are there any plans to add SagePay/Protx to the list of payment providers?
Yes, full API will be provided to integrate any payment gateway you so choose.- Would the new API allow for the development of a custom payment module (i.e. for SagePay/Protx)?
"Soon" as in weeks or months?