I was wondering if it is possible (with any reasonable amount of work) to add another mode line (i know there is the configurable header line), maybe right above or below the new mode line or even one under the mini buffer for the whole frame (like if i was running Emacs in tmux or GNUScreen).
In general, the fact that every window has only one mode-line is probably difficult to change (would require changes in the C code). Similarly, adding something below the echo-area is going to require changes to the C code.
What you can do is to add a special window at the top of your frames (and if you want it to only occupy a single line, then you can remove its mode-line (by setting
mode-line-format to nil for its buffer) and then fill its buffer with whatever you want to be displayed there.