This is something that's always bothered me, and short of 'make the text smaller' I've yet to find a real helpful solution to this anywhere.
As an example I'm going to be using this admin theme I randomly picked from a template site: http://iarouse.com/dist-rainbow/v1.1.1/index.html
You'll notice it has a multi-level navigation bar, which initially looks fine. However if you're in a situation like me, where I develop a commercial software package that allows third parties to add things to that menu, you run into a problem. The menu looks fine until someone puts a link with a long name into it. As an example here's one I've just added, and this is the name of an actual section in the software I work on:
As you can see, it looks pretty terrible now that it's got a long link. Now, the obvious solution would be to just axe the 'Management' part of the title - it'd still make sense as a link, and it's certainly something I could do if need be. But what about when that's not possible. What about when I want to do something like 'Domain Extension Pricing' - you hit a bit of an issue there.
As it stands I don't see any way of getting around this. Am I missing something or is this something we all have to live with?