I can only speak to the PADI version of the DM course.
At my LDS it takes a few months as a minimum to complete. There are many pool sessions to work on and develop skills to the appropriate level. Typically the course runs with one pool session per week. Also, there is usually one class session per week, so all of the theory takes some time to cover, as does the time to complete the exams. Much depends on the instructor. The instructor I had was a bit more flexible in when we could take the exams. That is, we did not have to take them all as a group in one sitting. When we had done the class work we could set up a time at the LDS to go and write the exam.
Once that is over it is up to the candidate to set up working as a DM in Training and coordinate with what is happening at the shop. If there are six candiadates in the DM class, then it will take them a bit of time to coordinate working with an instructor on courses (especially during winter, cuz it it a bit difficult to get an open water class done when the river is frozen). What seems to hold up the progress is the site map. For some reason this seems to be the biggest challenge just for folks to get moving on it.
I managed to complete the course in three months, but it was not easy. Pretty much had to give up most weekends once I was set to start the internship part.
As for taking a week or two, I suppose that were you in a resort with a good throughput of students that may be possible.
There were five candidates in my DM course. Two went on to become instructors in fairly short order and now live in Australia. As far as I know I was the only other person to complete the internship. The course was during 2004. IMO it is as much about the motivation of the people on the course as it is how the course is structured.
