I don't think this will help much, but for individual commands, you can sometimes use the
flag to change where a window opens. For instance, I set up an alias for Emacs
Code:
alias emacs='emacs -geometry 90x70+0+0'
that uses this flag. Like I said, it may not help you in your pursuit, since you are looking for a more global solution. Maybe it will create an idea or two from others.