Finally, after having a dozen 15 - 30 minutes sessions with different attempts at creating my own custom menus with WaveMaker, I managed to do them - almost as I wanted.
I think the big problem was that I began with implementing a lot of function I thought I needed, thereby overriding mixins and superclasses (yes, I forgot to call them, ta!).
Then I carried on in same vein, by mismanaging the information about which element to use for what, et.c. Now that the menus are (sort of) there, I need to do the following;
1) Dig up my old JDA Composer II template, where I had menus up and down the page and copy some code,
2) Find out a way to easily connect event to the menus (Can probably snarf stuff from existing components)
3) Meditate upon the best way to add new menus and submenus (i already have a custom 'submenu' widget which I can use as substrate)
But all in all, I managed to nail one out of 120 point in my wish list - not bad!