This title was announced for fall 2002 in the News section of the Tribes 2 browser on April 5th. Here's a link to GameSpot's preview.

Here's the thing I found most interesting:
Tribes Fast Attack will also come with an enhanced version of Tribes 2 that includes two exclusive mods. The Competition mod is designed specifically for league and tournament play, and it has faster movement and recalibrated weapons. The Team Rabbit 2 mod was created by Michael Johnson, the person responsible for the Team Rabbit mod for the original Tribes. It lets teams of four to six players compete in a capture-the-flag-style match that awards extra points for speed, style, and multiple passes.
The game's suggested price will be $39.99, and a $20 mail-in rebate will be available to those that own Tribes 2.