Mitcho, how about adding an option to configure the list in the widgets?
In the display options you allow Before / after related entries: which defaults to a label and <ol>. I changed this to <ul> expecting this to carry through to the widget. However this only affects the display of the related posts after the post.
However, the widget is hardcoded with <ol> (whereas I'd like a <ul>).
How about carrying through the configuration from the display options, or adding another configuration option for the widget?
(I just edited my copy of yet-another-related-posts-plugin/template-widget.php but I need to remember to update that with a YAARP update).
http://wordpress.org/extend/plugins/yet-another-related-posts-plugin/