Found this early in the morning, ended up staying up considerably later than I had planned. Downloaded, installed, but ran into errors. Could not get things to work. After removal and re-reading, another reason I don't work so late usually, I found that I was needing to rename the folders with a _ instead of the - that is in the tar.gz filename. So, after re-uploading and installing, then renaming correctly, everything worked great.
The quality I am seeing is on par with many paid professional apps/add-ons for use with email.
Cheers for a job well done. I do hope you keep it up to date as Roundcube, which was a nightmare in itself to install as my servers scripts repository hasn't been able to maintain the webmail interface properly, is updated.
As Roundcube is working on a responsive mobile design, I think they should get with you to use your design with a few tweaks here and there, for maybe a touch easier navigation within the menus.
Overall, I'd highly recommend this skin and plugin for anyone needing a mobile version of Roundcube.
Thanks again for taking the time to write this for us out here in the world.