Google's showing no signs of slowing its pace of Android development, with Android 4.0 appearing on the Galaxy Nexus late in 2011, followed in July of 2012 by the Android 4.1 Jelly Bean release that arrived powering the super Nexus 7.
But, forward-looking, update-obsessed people that we are, we can't help but imagine how Google's going to maintain the pace of innovation in its next version of its mobile OS, Android 5.0.
All we know so far is that Google's working away on the K release of Android, which it's developing under the dessert-related codename of Key Lime Pie. Regarding the version number, it's likely that the Key Lime Pie moniker will be given to Android 5.0. We thought we might find out on 29 October 2012 but as yet there is no official word from Google.
So now as we wait on official news of the Android 5.0 release date and features, we can start to pull together the Key Lime Pie rumours from around the web, with the first sighting of Android 5.0 on a benchmarking website, apparently running on a Sony smartphone. There has previously been speculation that Sony is in line to produce the next Nexus phone, which may lend some credence to this rumour.

Android 5.0 release date

Google has announced that its next developer conference - Google IO - will take place from May 15 to May 17 2013, a month earlier than 2012's June dates. Given that Google announced Android 4.1 Jelly Bean at 2012's IO conference, it's not unreasonable to expect to see Android 5.0 at this year's event.
Google IO 2012
Androids out in force at Google IO 2012

On 31 January, a Google IO showing of Android 5.0 looked more likely when screengrabs of a Qualcomm roadmap were leaked, showing Android 5.0 as breaking cover between April and June 2013.

Android 5.0 phones

Rumours of a new Nexus handset started trickling in during the third quarter of 2012, as we reported on 1 October 2012. There was speculation that this phone would be sporting Key Lime Pie, but sources who spoke to AndroidAndMe correctly claimed that the handset, which turned out to be the Google Nexus 4 would be running Android Jelly Bean.
While the Nexus 4 didn't appear with a helping of Key Lime Pie, speculation that we reported on 21 January 2013 suggests that the Motorola X Phone is the Android 5.0-toting handset that will be revealed at Google IO. According to a post on the DroidForums website, the phone will also feature a virtually bezel-free, edge-to-edge, 5-inch display.
The same leaked Qualcomm documents cited above also made mention of a two new Snapdragon devices, one of which will be, unsurprisingly, a new Nexus phone.
That Nexus phone is most likely the Google Nexus 5, though we'd be surprised to see it break cover at Google IO, given that the Nexus 4 only went on sale at the end of 2012.
On Monday 18 March, supposed images of the Nexus 5 surfaced, with the handset apparently being manufactured by LG. If the accompanying specs, leaked along with the photo by the anonymous source, are true, then the Nexus 5 will feature a 5.2-inch, 1920 x 1080 OLED display, 2.3GHz Qualcomm Snapdragon 800 processor and 3GB of RAM.

Samsung's Android 5.0 upgrades

Although Samsung is yet to officially confirm its Android 5.0 schedule, a SamMobile source is claiming to know which phones and tablets will be getting the Key Lime Pie upgrade. According to the source, the devices set to receive the upgrade are the Galaxy S4, Galaxy S3, Galaxy Note 2, Galaxy Note 8.0 and Galaxy Note 10.1.
Samsung Galaxy S4
As you'd expect, the S4 will be getting an Android 5.0 update

Android 5.0 features

For 24 hours, it seemed as though the first kinda, sorta confirmed feature for Android 5.0 was a Google Now widget, which briefly appeared in a screenshot on the company's support forum before being taken down. As it was so hurriedly pulled, many people assumed it was slated for the big five-o and accidentally revealed early.
As it happened, the following day, on 13 February 2013, the Google Now widget rolled out to Jelly Bean.
On 28 February 2013, we learned from Android Central that Google is working with the Linux 3.8 kernel, which gives rise to the notion that this kernel might make it into Android 5. One improvement that the 3.8 kernel brings is lowered RAM usage, which would mean a snappier phone with better multitasking.
While we wait on Key Lime Pie features to be revealed and scour the web for more Android 5.0 news, TechRadar writer Gary Cutlack has been thinking about what we want to see in Android 5.0 Key Lime Pie. Hopefully the new mobile OS will feature some of these things. . . .