Some info here, a report from the 4th International Ibogaine Provider's Conference in Durban, South Africa last month (relevant info towards end of report). The ESC is launching "The Iboga Dialogues" specifically to look at the issue of iboga sustainability. It's not good news. But it does seem like there is a potential for ibogaine production semi-synthetically from voacangine sourced from Voacanga africana. Lots of work to be done.
http://ibogainealliance.org/durban-2014