Mike Stall is one of the devs on our base services team, and his focus is on managed debugging. I played football with Mike 4 flag football seasons back, but generally don't need to work directly with him since the debugger and security don't have very much interaction.  However, Mike is always the guy to go to whenever there's a debugging question, so I'll definitely be reading his blog with interest.

Some of the topics he's already covered are mdbg and the ICorDebug interface.