thanks everybody for the help provided here!
I want to share a small addition that might be useful to others:

to make the menu-bar fit in the screen together with the minibuffer, I have taken the following steps:
1) choose a smaller font for the menu.
2) take into account the space used for the menu-bar in the computation of the size of the maximized frame.

point 1 is explained here.

point 2 is also comparatively easy. open the maxframe.el file and look for the place where the mf-max-display-pixel-height function is invoked. this is where the name of the function appears between single parentheses.
replace (mf-max-display-pixel-height) with (- (mf-max-display-pixel-height) (cond (menu-bar-mode 32) (t 0)))

that 32 is hard coded and you might want to recompute it if you use a different font for the menu-bar. it works for me in combination with Droid Sans Mono 10.