James Golding was kind enough to point me in the direction of this line: https://github.com/EpicGames/UnrealEngine/blob/ab237f46dc0eee40263acbacbe938312eb0dffbb/Engine/Source/Runtime/RHI/Public/RHIDefinitions.h#L814
You can increase it and it will work! (tested on Mobile Preview Renderer, Nexus 5 and Nexus 9)
Deducing from what Eric says however, this may break compatibility on some lower end devices (though I might be wrong about this) Eric do you know why this solution may be undesirable?