I know the List category posts has an attribute to show only an excerpt from the post, but I can't seem to get the plugin to work for the Wordpress tag break. Does the plugin recognize the tag?
Create a new List category template and then use the following code to get the part of the post before the more tag for display.
If you are interested I am creating a List category template for use with the TwentyTen theme - specifically for use with a page template that will be used to display WordPress pages in custom Facebook tabs. Let me know and I'll get it to you.