Found few moments ago on twitter:
http://contentisking.textmaster.com/en/2014/09/24/5-best-practices-for-localizing-software-applications/
just few basic rules never to forget. 8)
This reminded me about something...
There were few places when I had to fit text in small box, not always it is possible, for example login box in header.
Could you add something like this: http://jsfiddle.net/4gs5a55w/2/ to auto resize input fiels based on placeholder length?
As you can see there is no size on input, but all text is visible, no matter how long it is :)
Should be able to add that to theme.js with some tweaks ... like make sure there is a place holder, and don't let it go smaller if a size is defined.