I have developed a new extension for the BlogEngine.NET platform.  It's basically an enhanced version of the BreakPost extension.  It works the same as BreakPost in that you insert "[more]" in the post body where you would like it to break and display a link to the full post.  However, I added a couple new features. 

PostTeaser differs from the BreakPost extension in that it ensures all tags opened before the [more] are closed, so that the post body is still valid XHTML even after it is truncated.  I was having problems with BreakPost not closing my paragraph tags and throwing off my layout, because it was doing a simple substring. 

I also made PostTeaser display the post teasers in the RSS feed the same way that it does for the post list on the default page. 

Click the link below to download the PostTeaser Extension.