Xavier,
I have a couple of clients who are looking for subscription models, and shop trading also, i notice that HikaShop are still saying to use Akeeba Subscriptions, when there is a formal announcement that it is not support. When you were at the Sydney JoomlaDay2014 your team mentioned that you were looking into developing this as an in house feature, how has your team gone with that?
akeeba-subscriptions.html
This is a bugfix release. All users of the 4.x versions are recommended to update. As announced in November, this version has removed most of the payment processor and integration plugins. Otherwise. Akeeba Subscriptions 4.x merges all the features of the older Core and Professional releases.
This is a developers' product, provided without any kind of support. If you opt to use it you agree that you do not expect to receive any support from us.