I've updated the article The Trouble With ASP.NET Menu with a link to your forum post to make it easier for people to find out about that solution. Thanks for posting it!
It is a clever solution but I'm not sure I want to bake that in, I'd rather let people decide if they want to go with that solution and do it themselves for now though I don't rule out the possibility of reconsidering it later. The other solutions work well enough and I haven't had any problems with designs I've created in Artisteer. You can see on our demo site a bunch of new skins created with Artisteer 3.1.
While your solution probably is fine for most cases, my only concern would be that people who may have implemented custom features using ASP.NET Menu may need that script for other things such as postback which we don't use in our site menus but is is a supported feature of the ASP.NET Menu control.