First, they have released a software image for the Google Nexus Player that has early Vulkan 1.0 support. The Nexus Player has PowerVR G6430 graphics via the Intel Atom Z3560 SoC. This Android 6.0 powered media player could be an interesting little $79 Vulkan test device for Android fans. Then again, many continue to be frightened by PowerVR and Linux drivers in the same sentence. :/
The other ImgTech Vulkan bit is that they have published the source to their Gnome Horde demo, which they've been demoing for some months -- going back to SIGGRAPH 2015. The source code for this demo is designed for Android, but I'm told by Imagination that it might build for Linux, otherwise with being open-source could be ported.
Find out more about Imaginations' early access Vulkan goodies via this web page.