Alrighty, I leave you with a Norman WI:
Instead of being married off to Emperor Henry V, Matilda, daughter of Henry I of England, is married to Roger II, Count (future King) of Sicily. Let's have brother William shuffle loose the mortal coil before his father as IOTL, leaving Matilda the only heir (or at least Henry's only living issue) to the throne of England. With the support of the rather wealthy Kingdom of Sicily, Matilda's bid for the throne is rather stronger, and she becomes Queen. Their child (a not dead Roger, Duke of Apulia) would be heir to both of the Norman Kingdoms. What d'ya think, AH.com?
[Waits to be savagely mauled by the British board members for some egregious error in English history]