When ordering backshells from Glenair:
The rectangular backshell online catalog here has both D and MDM:
http://www.glenair.com/backshells/rectangular/index.html
each of which shows all of the models with pictures and links to the datasheets. Despite the simple model numbering format given on these top pages, some of these backshells have an actual part number xxx-yyy<+stuff>, while some have xxxTyyy<+stuff> where T is for top exit for wires. Plug the first part of the actual part number, not the simple model number, into the parts search here:
http://www.glenair.com/html/sameday.htm
which is also the 4th link down on the right of the company's home page, and get back exactly which part numbers (i.e. which options) are kept in stock. The home page also has a link to a page showing their distributors, the only recognizable ones of which are TTI (good web site) and Arrow (can only read their site with firefox).
Only a range of in stock part quantities is shown, and if you call glenair sales they still won't tell you exactly how many are in stock, but apparently no matter what there's only a 2-3 day lead time if it's on the list.
