As you progress with converting existing dialogs to the TileView widget and adding new dialogs that use the widget, have a look at what behaviors should be common to all the dialogs. For example, I would think that users would want to control the size of the tile (as is done in the Symbols dialog).
I've noticed that symbols, patterns and swatches are very similar in the way they can be stored, rendered and presented to the user. They are all fragments of SVG documents, usually stored in /shared directory. When I finish implementing model for strong paints I'll see if it's usable for symbols. It seems to me much of the code can be shared.
In addition to symbols dialog, size of the tile and fitting into tile will be controlled in swatches dialog. TileView widget supports it. I have to choose what kind of UI to use for setting the size. Currently the symbols dialog uses buttons at the bottom, while existing swatches dialog provides menu with options to control the look. In addition to this, in my proposal [1] I sketched a dialog for TileView configuration, but now I see it using it would mean a lot of clicking.
[1] https://www.dropbox.com/s/vupc7hl7wwsxsj1/new_patterns_ui_3.png
Tomasz