Try this for starters: Search for "You Comment, I Follow You.", Check source to be sure, Use seo plugin for FF for PR. Odd question if those are are yours in your sig.
First thing if you really believe that Page Rank still holds any relevance within the serps your mistaken. Personally I run a couple blogs that have the no follow removed from the html>> http://makemoneydontpay.blogspot.com/ and http://marketing-a-website.blogspot.com/ If your looking for search engines that search do follow blogs you could try> http://www.seopositions.net/dofollow/ and also their is a do follow directory>> http://www.dofollowblogs.com/index.php?c=0
Google "DoFollow Search Engine". That's what I do. Have to watch out...sometimes the sites listed are blogs but not doFollow.