In what is looking like a trend today (if two posts can be considered a trend), there's another LEGO bit of news today, this time involving Halo. However since this is appearing in EGM's April edition it's likely their idea of an April Fool's joke. It's tough to say though as this issue is already on newsstands and we've just entered March.
Also, I don't find this to be especially outlandish, certainly not any more than the Batman game posted earlier today. Personally, I think a Halo LEGO game could be every bit as successful as the other games in the LEGO franchise.
Feel free to tell me how utterly wrong I am.