Tcl/Tk is "known" for its ugliness to many developers but to them I can only say: you are living in the past. The tile theme engine is certainly not a one trick pony, but has a lot of functionality to offer that is not immediately obvious.
I think it was in the news group comp.lang.tcl where I read that it is possible to make a themed text widget on Macs and get the typical borders, even though the text widget does not belong to the tile widget set. The essential part is to use a ttk::frame widget but with a style from the entry widget, like
ttk::frame $w -style TEntry which is not a totally obvious solution. Inspired by this a managed to create a text widget with custom borders using an image element:
The complete test code can be found in the coccinella cvs at SourceForge: coccinella/contrib/tileutils.tcl. This also includes a short demonstration of my tkpath package for creating images directly by drawing commands.
Sorry for the very 10.2'ish Mac look.