I definitely agree that we need to get this change into squeeze and that we need to be careful to not get into bikeshedding about names. On the other hand, choosing a group for a purpose like this should imho be done carefully as changing the name later is hard if not impossible.
Since this group would be Debian-specific, how about "Debian-admin" or "Debian-sudo" (as in "Debian-gdm" or "Debian-exim")?
- Fabian