Any rough guesses on when staking will be implemented?
We're down to discussions on just what form it will take so the rough guess is "soon," possibly "very soon" and "definitely within the next few months".
Naturally
a lot of "what if" scenarios are examined before any changes are made and without preempting the core group's decisions in any way I can tell you that a 2% compound interest has been well scrutinized.
A couple of interesting features of that inflation rate are that
it would restore the number of burnt coins over 7 years and,
if deemed desirable at that future time, can be left in place for
75 years without exceeding CannabisCoin's original intent (back when it was launched as a scrypt coin) of 420,000,000.
Again, that's my observations and the core group may decide otherwise if it is deemed in everyone's interests.
Edited to highlight "what if" speculation far into the future.