I don't know how possible it would be, but this sure might be an awesome utility...
A javascript utility to run on your menu code that analyzes which functions you're using and not using... which will strip out the unnecessary code, leaving u with the bare-bones minimum you need for ur specific implimentation.
Ok, I know.. I may be dreaming... but ah well... I can dream
I'm just wondering how much overhead can be cut from the menus if you were able to streamline the code only down to what is used versus what is available.
If you're able to pull it off, I think it will also help you manage the size of your code better as new browsers and features are relased... I'm sure you are struggling to contain that code size now as it is.