This guy, Marius Silaghi, is doing a great work by coding (C++) a 3ds max plugin to implement chamfer functions.
At the begining, it was just a script, destructive one (http://www.mariussilaghi.com/qchamfer.htm), but now he built it as a modifier,
ie, user can adjust what was already applied.
Imo, considering the speed Silaghi codes, this will be part of a future 3ds max release.
Very inspiring to coders around.