This function is still high on the wish list, and will be added to the XOOPS 2.1 roadmap, if I have anything to say over this (wait a minute, I actualy do! ). Dropping this at the XOOPS Module Development site will do you no good at the moment, not much happening there.
However, why not use an existing dmtml script, the main menu block code and create a new module (like iMunu did) that adds an alternative menu, not as a block, but as a theme integrated smarty variable? Then you could put it anywhere you want...
Just my 2 cents
Herko