Reported on Toysdaily, Gundam Ultimax is an ongoing Gundam mecha design series by S. Shimizu. The first issue was released in December 2007, and Volume 2 was out April this year. Many unconfirmed settings for many mecha from various Gundam series are available in these two volumes, including the very new Gundam Double O series and Gundam Unicorn.
Volume I has Gundam Exia on the cover, while Gundam Unicorn is on Volume II.
Some of the work you can get in these two volumes, including Dynames, Virtue, and Tieren Jiu Long - a totally new fan design.
The bad thing of it being unconfirmed means that you won't be able to find it on websites like HLJ, Hobby Search, or even Amazon. Folks who are interested in Gundam Ultimax can get it from MelonBooks. Each volume is 1,050 Yen (inclusive of tax).