Seems that I almost solved the problem with interface blocking during long i/o calls.
The solution with gobject i/o Martin Grimme advised is working nice on tests (i.e. I can run other shortcuts during long call and interact with other widgets) when running both as standalone script and from hildon menu.
I'll post a patch this night after making my code more readable

P.S. Discussing with Andre Klapper is almost always useless so don't ever spend your time trying to explain him anything. Seems that he lives in parallel universe so trying to communicate with people in this reality is a hard task for him