I knew about it, check this aritcal from http://aeug.blogspot.com/
Here what it says :
Gundam SEED 2 rumor #5839385
SEED 2 rumor has once again surfaced this time courtesy of Bandai and Sunrise themselves. The rumor first started surfacing based on Bandai's job fair (aka company explanation to the recruits). Apparently, one of Bandai's Human Resources personnel said to the possible recruits that SEED 2 will come out this fall. A second rumor appeared after Sunrise held their job fair, which occurred on April 20. Here, Sunrise staff mentioned SEED 2 is in production with Oct 2004 premier in mind. The information of Sunrise's job fair was posted on this Japanese BBS.
UPDATE: Due to major mistranslation by one of the anime sites, here is the quick summary of the post.
At Sunrise's job seminar/recruit, one of their recruiters mentioned SEED 2 was under production with Oct 2004 schedule. The poster, who attended the seminar, also heard that Inuyasha is going to end this Sept (NOTE: Sunrise produces Inuyasha, however Nihon TV airs Inuyasha not TBS/MBS, which aired SEED. No where does it state that SEED 2 will replace Inuyasha's timeslot). The poster then assumes one of the anime magazines must be close to making an official announcement based on what he heard at this seminar/recruit. ΒΆ 3:46 AM