All sound strategies here.
I've found that publishing genuine, in-depth blog comments often leads to blogging friendships which produce Do Follow, short and sweet mentions on blogs. Or, these relationships produce guest posting invites which lead to highly coveted Do Follow links. I landed Do Follow links from Pro Blogger, Smart Blogger, Blogging Tips Dot Com and Blogging Wizard, in so small part because of genuine blog commenting. I build relationships with Adam, Zac (who owned Blogging Tips Dot Com at the time) and Jon's and Darren's contributors, through genuine comments, and the backlinks and guest post invites came later.