'Twas nothing but a rumour but I can now say that Halo DS was made, but will not be released. The source of all evidence on Halo DS refuses to provide any evidence as to why the game wasn't released, but they have provided video evidence of the game.

Still, it is possible to layer the video clip with another video clip so it just looks like he's playing halo on the DS, and he doesn't look like he's doing much in the video, so we shouldn't single out all elements of doubt. Still, most "Garage Gamers" make fake games to say that they will be released, it's not likely for someone to go to the trouble of making a fake game just to say that it has been made and won't be released..
Then again, that means people will for ever believe their lie so it may be a possibilty. He may also be telling the truth. Personally, I would love a halo DS to be made and I would play it as soon it was released. Anywho, I've already spotted some flaws in this so called Halo DS.
If you look carefully at the game logo at the top of this article, you may notice that the D is exactly the same as the L with the top part of the O reversed. Even the | shape on the H isn't the same as the L, why would professional game makers use the exact same shape twice? Also, Halo have had Combat Evolved, no title and finish the fight as their games, unless the DS game was just an exact copy of the first halo game generated into a DS version, would they really repeat the same name?
Re-using but changing a name sounds like something a fan would do, not a professional game making company. Then again there's things like Harvest moon: friends of mineral town, and harvest moon: more friends of mineral town, so I guess it is used.
Also, he refers to the makers as “Big names” rather than as Bungie and Microsoft. Kind of suspicious.
Also, the thing which proves the guy who came up with all the stuff I've been talking about totally wrong, is that Bungie and Microsoft said that The DS is not suitable for FPS (First person shooter) games, which I quite agree with as the controls are very hard, so they said they would never make a game like this for DS.
If the guy who said that the game was made but wasn't released was telling the truth, he wouldn't be afraid to give this as the reason to why the game wasn't released. He wouldn't just not tell us anything about it.
Overall, i'd say this was just a joke and that Halo DS will never be released.
Anywho, it's a possibility. If the rumour was that it was going to be released, i'd be giving my hopes up for it, but since the rumour is that it was made but won't be released, I'm not really going to bother with it. Hopefully one that they really will make a halo DS. That would be great. Until then, I'm sticking with Call of Duty 4.
All the evidence is found here, and the quotes from the official companies is this:
UK, July 19, 2007 - It's a rumour that's been flying around the internet for some time but Bungie has finally admitted it's “very likely” another developer created a DS version of Halo. However, the dev said that there has “never been an officially funded or sanctioned development of any sort of DS Halo game” from Bungie.
Speaking to Siliconera, Bungie's Brian Gerard and Frank O'Connor candidly tackled the subject of Halo DS. They confirmed that “every once in a while it does come up” and that Microsoft could potentially publish it through THQ, as it did before with Age of Empires: Age of Kings on DS.
Having said that, O'Connor doesn't believe the DS is well-suited to the FPS genre: “The problem is the DS is not an FPS console, right? It's not an FPS handheld. There really is no such thing. If we did something cool I would like to see it. But I would rather see the Halo IP on any handheld system applied to a different genre because handhelds don't necessarily do FPS well,” he added.
So where does that leave Halo DS? Well, O'Connor thought that the brand could work better if it was “side-scrolling shoot-'em-up or whatever, but not necessarily an FPS” and that Bungie would never rule it out. “There is nothing going on right now”, O'Connor concluded.
If the Matt guy in the link I provided had been telling the truth, he would have said that because the DS was no suitable for a shooting game, they didn't release the game, he could have been telling the truth, because he provided no reason as to why the game wasn't released, I have every reason to believe that he was lying.
Still, once again, the guy in the link I gave said “Big names” but didn't give them, and Bungie said that another developer could have made the game, meaning that if another developer did produce a copy of Halo DS, then decided not to release it, that could be what "Matt" was talking about. Still, I doubt him.