Here's a pod for BlogCFC that will show some of the recent comments on the sidebar menu. You can adjust the number for comments shown and the amount of text to preview.

I'm using it now, and I've chosen to show the most recent 3 comments with up to 100 characters of text, which comes out to be about 3 lines.

To use it, first download it and unzip it into {blog}/includes/pods/.

Then to get it to show up in the blog, open {blog}/tags/layout.cfm and find the various cfincludes at the bottom which correspond to the calendar, archive, and search pods for example. Copy one of the cfinclude tags, and paste it in the position that you want it to show up. I have my recentComments.cfm pod under the recent.cfm pod. Save the file and that's it.

You could also edit the pod text style to match your blog theme.

Download Pod