Traditionally in the Android development cycle, major versions have launched at the end of the year (exception being Gingerbread/Honeycomb). According to the Wall Street Journal, Android Jelly Bean should launch this year, “by Thanksgiving”.
Will this be Android 5.0 or another version? That depends on Google's plans for their I/O developer event happening in June. Andy Rubin's team has two options: one, launch an Android 4.1 version with some improvements at I/O (and call it Jelly Bean), and then give a new name to Android 5.0. Two, use the event to showcase upcoming features of Android 5.0 Jelly Bean, and release it this fall.
Now, the rumor in WSJ says that Google is getting five manufacturers (probably Samsung, HTC, Motorola, Sony and LG – no love for Huawei, Google?) to release “Nexus devices”, all at the same time, this fall. How is this possible? Well, Google plans to give all of them early access to the next major version of Android, much like Microsoft does with Windows and WP7 manufacturers.
Google plans to launch the next version of Android with all of them at once , with some less important manufacturers launching a little later.
So what does this mean for us, the users? It means that we get to choose from at least 5 phones and maybe some tablets, too (some manufacturers will choose to release both a phone and a tablet), so our choices for stock Android devices will greatly improve. Even better, they will all be available from day one. That means that, if you don't like a particular Nexus device, you have several others to choose from, and you won't have to wait many more months until other devices appear.
This deal means that stock devices will flood the market. Also, manufacturers will have early access to the Android code, meaning that they will also be able to upgrade their skins faster and launch new devices faster. However, the first devices will still be only stock Android. And Google should make sure of that through a formal agreement.
According to WSJ, the Nexus devices will most likely be sold through Google's Play Store in US, Europe and Asia, which again is a great move for Google, because they'll be able to wrestle control over Android from carriers. It won't hurt carriers too much, because at least in US, most people still buy phones through carrier subsidies, but it should work very well in markets in Europe and Asia.
Overall, this is a very smart move from Google, that will benefit themselves, the consumers, and even the manufacturers.