Mobile Suit Gundam Unicorn is an upcoming serial novel by famous Japanese author Harutoshi Fukui. Character and mechanical designs will be provided by Yoshikazu Yasuhiko and Hajime Katoki, respectively.

The story takes place in Gundam's Universal Century timeline and begins in UC 0001, at the very beginning of human space colonization. It is said to cover an as yet unspecified major event that influences the course of human history forever. The main story takes place in UC 0096, three years after the events of Mobile Suit Gundam: Char's Counterattack.

The main characters

Barnarge Lynx : A 16 year old boy who is a student at Anaheim Industry Technical School in the colony "Industrial 7". He is described as seeing war as something akin to fiction, as he was born after the One Year War ended and did not experience the more isolated wars that followed it. However, upon meeting Audrey, he is drawn into a new conflict.

Audrey Burn: A 17 year old girl from a noble family, whose life changes after she meets Barnarge. Her name appears to be derived from famed actress Audrey Hepburn. Recently revealed herself as Mineva Lao Zabi.

Full Frontal: A mysterious leader of Zeon remnant forces who is described as the "2nd coming of Char". Like Char Aznable, he is a blonde man whose face is hidden behind a mask, and he wears a red uniform and pilots a red mobile suit. Whether the name is an alias is unspecified. Name could be short for Full Frontal Assault.

The main mobile suits

RX-0 Unicorn Gundam: A pure white MS produced by the "UC Project," part of the Federation Space Force's reorganization plan. The entire movable frame of this experimental machine forms a psycoframe, and its responsiveness is incredibly high. It also incorporates a special "Laplace Program" OS and a system known as "NT-D." When NT-D is activated, the internal frame expands and the entire figure is transformed. In the process, the armor separates along its seams, and slides are released. A red glow can be seen where the internal frame is exposed by the gaps in the armor, and this is believed to be a psycoframe luminescence phenomenon. The machine's performance, in particular its mobility, is dramatically increased when NT-D is active. In this normal mode, it resembles a normal looking mobile suit.

RX-0 Unicorn Gundam (Destroy Mode): The Unicorn's appearance when the 'NT-D' system is activated. In this form, the psycoframe built into the entire body's movable frame reads the pilot's thoughts (psycowaves) and directly influences the unit's movements. In other words, the MS can ultimately be controlled by thought alone. However, when compared to one's idea of how a human body works, the stress of gravity on an 20 meter MS (more than 10 times the size) is extraordinary. Aided by the psycommu, the pilot's mind can only endure about five minutes of operation, after which a limiter is believed to activate, returning the MS to normal Unicorn form. Furthermore, the system activates not according to the pilot's discretion, but automatically when certain conditions, as yet unexplained, are met. In this mode, the mobile suit resembles a standard Gundam.

MSN-06S Sinanju: Personal machine of Full Frontal, it strongly resembles the late Char Aznable's MSN-04 Sazabi. Developed by Anaheim Electronics, it equips a psycoframe and served as a testbed for the NT-D System. The resulting data was used by Anaheim to complete the RX-0 Unicorn Gundam, and the Sinange was subsequently stolen by Neo-Zeon in UC 0094.

A machine developed by Anaheim Electronics to serve as a testbed for the NT-D system, part of its movable frame forms a psycoframe. The resulting data on the machine's improved power and responsiveness was then used to complete the RX-0 Unicorn Gundam. Stolen from Anaheim in UC 0094, it is currently the personal machine of Neo-Zeon ace "Full Frontal", and bears a strong resemblance to the late Char Aznable's MSN-04 Sazabi.

You can take a look at the mecha designs at MAHQ and the Japanese official site. The official site also has an overview of the main characters.

The novel is out in Japan (September 26th). And although it just came out, the merchandise for Gundam Unicorn is already being made and developed. See pictures and magscans of a 1/100 Prototype MG(?) model kit at Danny Choo and at Super Robot War Hotnews.
A promotional video (filmed with a cam, no direct feed) for the Gundam Unicorn graphic novel can be seen below or downloaded from Rapidshare which shows some illustrations AND some animated footage at the end which makes the rumour, that an animated series will accompany the novel, more credible.

Nowhere is spoken about a manga or graphic novel. And although the post is from June 12th, scans from the first 4 novels can be found at Super Robot Wars Hotnews.

Gundam Unicorn Promotional Video: