We ran into a limitation of IE where it only allows 31 stylesheet objects on a page . This includes objects declared using a <link ..> tag as well as objects declared using <style ..> tags.
Because we have a pluggable architecture for our CMS, and each plugin is loaded into the page when it is first used, whereby js and css resources are loaded using ajax, we run into this issue quite quickly when the user clicks around for a while.
We have found a work around by adding the stysheets as @import statements to a dedicated <style> element, instead of adding them to the head as a link.
I've created a patch for wicket that implements this approach. However, I am not sure if the patch is entirely to the community's satisfaction because the way one can programmatically add imports to a stylesheet doesn't allow setting the type attribute (ref attributes are not possible at all in css @import statements). Which consequently gets lost with this approach.
On the other hand, I imagine others will sooner or later run into this limitation and want this workaround to be available to them.