The links below are for the Video Entertainment System retrofit WIS and also to the benzworld.org publications that I had done after my retrofit.  The VES is no longer sold by Mercedes but you can find some online accessory stores that sell new ones.  Potomac German Auto and Engisoft are two that have them discounted at a very reasonable price.  These kits do not come with the DVD player, only the VHS player, but there are sources for the OEM DVD player popping up all the time and Potomac is supposed to be offering them very soon ... I have one in my ML now!!!