One thing you should definitely use is the firefox "nodofollow" plugin. You'll see that 90% of the so claimed "do follow blogs" are not even do follow comments..
Try this... this sites have a huge list of do follow links... http://dofollower.com/ http://www.inlineseo.com/dofollowdiver/ http://www.commenthunt.com/ http://www.ezbusinessneeds.com/dofollow.php
The blog in my signature accepts comments and maybe you can find some information their that could help you improve your blogging experience.
I think you would have more luck getting one of those automated tools that seeks out do-follow blogs in your category and also ranks PR + if comments are open etc.. just make sure your commenta add to the site or they might not pass moderation..
According to my findings, I believe that the blogs which are moderator based are mostly NO Follow and the comments which aren't moderator based are Do Follow. what do you say friends ?