I guess you must find blogs with that kind of PR and post blog comment. The problem with blog comments are they are mostly removed or mark as spam even they are not really spam.
Its hard to get that backlinks unless you can asked someone to do some link exchange with your site or if you have the money to spend in buying those links. You can also try blog commenting
One way to get high PR backlinks for free - design a high quality website with lots of interesting and useful content or functionality. Does this describe your site? If not, then why do you expect free backlinks from high PR sites? You need to give them a really good reason to link to you, if not you are wasting your time and should do something else if you want good quality, free links to your site.
Build your pagerank first if you want PR6 and above for free. Start with blog posting, social networking, link exchanges, and so on to build your site's rep, then work toward the higher PR sites. Remember, it doesn't happen over night!
I agree with commenting on as many blog posts you can, but make sure they are not meaningless junk comments. This are almost always discredited. Also, almost all of those PR5+ blogs use no follow rel links.
I think you are trying to get to the top to fast. Try and build your page rank then the higher page rank sites will link to you. Just get pr3 and pr4 for now the rest will come at a later stage
Your sites are set too high. If you are not an authority sites you need to build some a lot of links and get pr2 yourself. After that target page rank 3 or 4 sites, in fact some will find you.
More than likely this is correct. Anywhere you can get a link like that for free is not going to be a pr6 or higher.
To get links of that caliber, you will have buy them. It's not cheap, but if you can afford it, it would be worth the investment. Anything of pro-longed quality on the internet will incur a price. You must ask yourself if you're willing to invest to further your business.
Partner that's like asking how you get a mansion and a Mercedes for free. I guess figure out a way to steal them lol, otherwise I think you're dreaming.