Found the following from a Wong Kar Wei fan site:
Here's a detailed explanation of why it isn't available, from Mobius Home Video Forum:
...actor Forest Whitaker, who has an uncredited appearance in the short film. One of the reasons Whitaker agreed to appear in THE FOLLOW was with the understanding that it would only been seen on the BMWfilms.com website.
As you already know, a total of five short films were produced by BMW for viewing as part of a promotional internet campaign. Later on, BMW produced a private, in-house limited-edition promo DVD entitled THE HIRE that featured all five of their internet shorts and numerous extras -- and everyone wanted to get their hands on a copy. Due to the high demand, plans were made to release a publically-available DVD promo. And this is when the problems arose -- Whitaker and his agent contacted BMW and requested that THE FOLLOW be removed from any future DVD releases.
Because of the details of his original contract (and personal reasons involving his appearance), Whitaker and his agent COULD -- and did -- make this demand. Remember, THE FOLLOW was initially created solely as an online promo -- releasing it later on as part of a full-fledged DVD edition is a completely different beast than their original "internet only" plans and contracts.
BMW did attempt to re-negotiate with Whitaker -- both monetarily and otherwise -- but to no avail. Whitaker simply wouldn't budge, and BMW had no choice but to comply with his request. That's why THE FOLLOW did not appear on the "Vanity Fair" promo DVD nor later repressings of THE HIRE, and can only be seen online. (With regard to BMW's original "limited edition" DVD, THE FOLLOW was able to be included in that set because it was a private promotional release.)
So there you have it. From what was hinted to me, Whitaker's stance was due to personal reasons more than anything else. As to what those "personal reasons" might be, I couldn't tell you, nor do I want to make any conjectures about it. My understanding of the situation is that BMW could still release THE FOLLOW on a DVD if they edited out Whitaker's scenes, but something that drastic isn't likely to occur -- they want to leave the film as it is. If you're one of the lucky few who managed to grab a copy of the original, unedited promo DVD, be very thankful -- THE FOLLOW isn't going to make an appearance again at any time in the forseeable future.
I've ripped 2 versions of The Follow from the DVD - a skinny 15MB version for those on dialup, and a full-detail 90MB version for those of you with broadband. Can only host it for 48 hours on my server - so keep your eyes on my journal - been having some difficulting properly uploading the film, but will hopefully have it ready for download soon.