+2  A: 

Instead of creating a reusable class you might consider reusing your style with a Silverlight 3 BasedOn style:

http://community.irritatedvowel.com/blogs/pete%5Fbrowns%5Fblog/archive/2009/03/18/Silverlight-3-%5F1320%5F-BasedOn-Styles.aspx

That technique will allow you to make minor modifications, like changing the row buttons in your example, to an existing style.

James Cadd
That was exactly the kind of feedback I was looking for. Unfortunately `BasedOn` only allows med to inherit things like property setters from parent styles. In my case I want to parametrize a single property (the `Template`) with values from a property on a visual parent.
Martin Liversage
Good point, I see why BasedOn isn't what you're looking for... and I flat can't figure out better way! Maybe you'll get lucky and a Xaml expert will post something elegant *ahem* Jeff Wilcox *ahem*
James Cadd