Interesting that no one seems to know the definitive answer to this.
I had never given it much thought before as I don't that often dive deeper than 30m but nevertheless how many DMs/Instructors have actually even ever taken the Deep Speciality?
Most of those instructors and divemasters who have taken a Deep Specialty are likely recent instructors who have taught way less divers and done way less deep dives than many experienced instructors and divemasters who have not taken a Deep Specialty.
What I find interesting is how many SB'ers seem to think no one seems to know the definitive answer. I just yahoo'd "dan dive insurance", then clicked on the first "hit" (DAN Insurance : Dive Accident, Trip, Dive Equipment, Camera, Group Term Life), then clicked on "Compare DAN's Dive Accident Insurance Plans" to get to this page;
http://www.diversalertnetwork.org/insurance/compare.asp
Now look near the middle of the page for "Planned Maximum Depth Covered";
Standard Plan - 130'/40m
Master Plan - No Limit
Prefered Plan - No Limit