If you want to work on such a port, you should better work with the current /branches/1.1 branch.
The reason is this branch is based on ioQuake3 engine and I know there're few projects with OpenGL ES you still can look at. As you should know, Tegra chip provides OpenGL ES support and Quake3, ioQuake3 and Smokin'Guns engine uses OpenGL (without 'ES', I'm not sure what are the real issues btw). You still can look at
ioQuake3 on N900. This is a port to a linux based system and the renderer has been modified to support OpenGL ES and sources are availables. You can also check
Kwaak3, ioQuake3 Android port but this one is using a java binding to start the game on a linux based system. These projects are actives but you may want also to look at
Q3CE project which is more in the WinCE spirit, you may find there some good code for the touchscreen support.
Honestly, on my part, I would really like to have time to work on
Kwaak3, ioQuake3 Android port Then I'll definitively try to help if you work on WinCE port. Also working with ioQuake3 based 1.1 branch, your work would be able to be integrated in ioQuake3 and so you may benefit from ioQuake3 team support.
And finally you should firstly try to work on Q3 or ioQuake3 port before Smokin'Guns engine port, so you'll definitively have support from many other guys than just us ! You should just know Smokin'Guns engine is not really different than Q3 and ioQ3 engine and the final backport to our engine will always be possible.