Although there have been leaks about the Nexus 6 and Nexus 8 in the Chromium code, the latest report from @evleaks states that there will be no new Nexus devices in the future. Evan Blass tweeted that "There is no Nexus 6. Farewell, Nexus..." which means that LG Nexus 5 is the last Nexus smartphone ever.
There have been rumours about Android Silver devices succeeding the Nexus line-up of smartphones and tablets but no one imagined that it would be as soon as this year. Probably, there would be multiple Android Silver certified devices by February 2015. Android Silver certified devices might come with high-end hardware, water-resistance, latest version of Android with minimum UI customisations and guaranteed software updates.