The Kings of this period were far more imaginative than we give them credit for: Henry VIII was offered variously the Imperial Crown, to be made Imperial Vicar, and even Milan: Charles V considered marrying Anne of Bohemia himself: there were plans to divide France in three: a separate Kingdom of Italy was definitely considered at some point. Just comb through contemporary diplomacy and you'll come across all manner of interesting proposals (that the eldest son and daughter of Mary Stuart be betrothed to the eldest son and daughter of Elizabeth Tudor, etc).
When was Henry VIII offered the imperial crown?