I've stumbled across Jason Hartman's media pricing page. Jason has a number of podcasts, but in this case this is regarding the Creating Wealth podcast. Jason is a successful business person and also does a podcast (that I listened to and reviewed on the Podcast Review Show) called “Speaking of Wealth” where he interviews podcasters (I swear he's going to write a book).
Jason's page says its been downloaded over 1,000,000 times
You can sponsor his podcast for $3,100 for 13 episode $238 per episode ($200 if you provide the 30 second clip).
When I went to his website, he had 257 episodes. This calculates to 1,000,000 / 257 episodes = 3891 downloads per episode.
If we then take $238 per episode and divide it by 3891 downloads = .0611 cents per dowload
To calculate CPM we times that by 1000 to get $61.16 CPM. This shows that Jason is someone who truly appreciates the power of podcasting. He knows Podcasting is Not Radio.