No, please don't use the keyword tactic. You should sign up for Matt Cutts videos on YouTube to get the latest news on Google updates. Guest blogging is an issue now, regardless of if the blog has relevant content for your business. The sites that show keywords in the names, I believe only appear after the commenter has been approved to comment but I could be wrong. I have seen a pattern here though. These sites also seem to be using 'commentluv' wordpress plugin.
If you get links they should be about your brand, not keywords. That is the end of story I am afraid. Follow your competitors, research your subject and publish good content on your own blog and share it.
Virginia