How large is your menu? I've created a php script to generate a menu with 100 main links, each with a sub menu of 20 links and each of those with a sub menu of 5 links, so that's 10,000 items. The only thing I noticed is that's a lot of html to spit back from the browser, so rendering is a little slow (on my box it was about 1 - 2 secs to load / render the page. But I doubt there's a cleaner implementation out there. At some point, shear volume of links will impact performance.