The original question has been resolved - under version 1.1.0 there are now 3 sizing options.
Regarding the unrelated issue raised by gab1982, there is no support at this stage for template tags. Part of the reason is I am not sure of the best approach for this. At present, the settings are contained in each widget. If you are using a template tag, the choice of featured product would have to be made somewhere else (possibly as an argument to the template tag). It is also possible that with version 3.8 of WP e-Commerce, you could use the new custom-post types for products to achieve this.