What about Vladislav of Syrmia succeeding to acquire Croatia but gets defeated by Waclaw III of Poland and Bohemia in Hungary but gets to hold Croatia.
I can't remember the detaiils but wasn't a Bohemia-Poland union on the cards at the start of the 16th century which then would have merged with Lajos of Hungary to create a combined state?
Sure, it has Croatia but it could cede that to Austria to get Imperial acceptance or something?