Mark Glaser’s Media Shift is outstanding–a reported media trends blog–and should be high on your list. That would be drop me to four in the way you have calculated it, I believe. (Fine by me…)

Media Shift is a PBS blog, part of that news organization’s larger and multi-stream domain. Romenesko is part of Poynter, a larger domain with many subscribers to many “products.” Both had substantial user bases before that, so it could be said they merged with their current sites.

If you consider merger into larger publishing and news domains one complication when you’re looking at subscribers, another would be bloggers who have more than one site, or stream for their work. Romenesko has his Obscure Store and Starbucks gossip sites.
Jarvis started Prezvid and there’s NewAssignment.Net and beatblogging.org that spun off from PressThink. If you asked how many subscribers Jarvis has, I would say he has the subscribers to Buzzmachine, his main blog, plus PrezVid. But if you are looking at press blogs, not bloggers, then the count you did is more valid. How many subscribers does Josh Marshall have? Well, it would be all the subscribers to Talking Points Memo, plus TMP Muckraker, plus TPM Election Central.