Scrapebox can currently do this.
You enter your keywords for your niche, load some proxies and then scan for the PR of each result. You then click the PR button and order by PR (ASC or DESC). If you need this data for later, you can export it as an XLS file.
I believe, though I haven't been able to figure it out, there is an option to set a "minimum" pagerank and truncate all the less-useful results.