H. 'Grand Prize'
This is a sport of 'Grand Tiara' has been in our yard since 2008. Compared to the parent it has lighter coloured margins in the summer, supposedly turning a creamy white. I'm not sure I'd call the edge 'creamy white' in this shot from mid-July, it looks about the same shade of white as the parent.
Because of the rhizomatous growth from members of the Tiara family, it is not uncommon at all for smaller divisions to almost fall into multiple divisions. That's what happened when I received my 'Grand Prize', and as you can see in this cropped version of the above shot, there's plenty of new growth shooting up, with the edge variegation being cream/yellow rather than the green variegation you see on fresh 'Grand Tiara' growth.
Here it is the end of April 2011 and you clearly see the creamy yellow edge it emerges with, quite different from its parent, which shows a pale green variegation when it emerges.
Some more info in Hugo's Database.