For dedicated server manager, you also have XAseco for example.
I don't think there are additionnal callback and stuff to be reveal for the release that we have not done in the beta. We will offcourse release new ones when needed for new features but we give as much as we can already. It is really in the continuity.
Nadeo Live have some engineers in-house and can also ask for external development later. If we do this, we have to make it on a core we master and manage. With ManiaLib and with the help of the former creator of Aseco, we have made ManiaLive to enable us to bring those development as far as possible, but XAseco is well supported and you can find good information here http://www.xaseco.org/
Maniaplanet is all about diversity.