1.1 is my max stable limit as well, but I usually just run at 1GHz for better battery life. My phone likes Slayher kernels better than any other it seems.
Regarding themes, I'm currently on Elite HD. I have Liberty installed but haven't tried it yet. And I just loaded, but also haven't tried, that awesome new Meizu M9 theme?
http://www.miui-dev.com/forums/showt...Theme-Meizu-M9
Thing looks amazing, but too incomplete to use yet.
What theme are you on?
Also, whenever I have had random reboots it was either a very buggy ROM (happened once with BB v5) or bad kernel (bad version or too high of overclock).