Sine.space by Sine Wave Entertainment is a multi-user virtual world based on Unity3D. Another blog post gives details of the development process for a custom region using content created in OpenSim and brought across to Unity3D via the OAR Converter.
I used the Unity3D Sine Space Base prepared as noted in the blog post and installed the OpenSim OAR Converter translated Epic Castle content…
The upload size was 285.19MB and the produced downloads for the various platforms were reported as:
Successful Platforms: win32 (184mb), webgl (127mb), android (194mb), ios (193mb)