Kojima has been hinting at a game that we all want to see eventually. Zone of the Enders 3, already somewhat announced, and yet still yet to be worked on. That is according to Kojima that stated it will be on the list of projects for the future, but not currently.
This is not a rumor," Kojima told jeuxvideo, "My team and I want to develop a new Zone of Enders. But it turns out that Kojima Productions has limited resources in terms of teams and directors. So at this stage we have not yet had time to work on Zone of Enders 3 which has been postponed at the calendar. However, I think after Metal Gear Solid Rising, I will look seriously [at] Zone of Enders."
Kojima is currently developing Metal Gear Solid Rising. The first, well Kojima studio first, game to see multiple consoles the day it comes out. The game also turned many heads during this last years E3 for its sword like gameplay and stealthy MGS qualities. Alongside that Kojima studios is also working on a 3DS MGS title, and has just finished Metal Gear Solid Peace Walker for PSP. Lets not forget Kojima's helping out with other projects such as Castlevania too! So its no wonder they are running low on resources.