I saw this thread today and read it all the way through. I was searching for keyword 'authority'.
Here are my thoughts:
Local (American) writers: If the writer knows something about the niche, then so much the better. But if you are writing about something you don't know nothing about (say 'fireplaces') then your skills are in reading and summarizing what is out there already. In that model, I am more biased towards a 'researcher' than a native speaker.
Authority Sites: As you have found out, authority sites perform. Why? because you can:
a) find out all the long tails pretty quickly and the staff is trained to write about that subject already - they know where to look for info, etc. etc.
b) you can get discount coupons from vendors - THIS IS BIG - and offers then for opt-in, etc.
c) you really know who the non-adsense advertizers are, and can work with them
d) your opt-in would be very rich, as you have found out, and maybe your biggest money producer
e) I have heard you get much better price on Flippa for the same revenue
f) if you have g analytics, then visitors are staying on your page way longer, and I think google would weight that greatly.
The cons are it is a big investment, so you don't want to be slapped. Link building is harder, probably involving guest posting (again not hard if the staff is already focused), etc. Maybe not doing the paid blog networks, etc. Yes, I think linkbuilding is the real 'con' in the authority model. But then google trusts you since it knows you are not going to be crazy stuff with a 100+ page unique content sticky site. Panda follow ons, IMO, will start to give better rankings to such a site.
I am personally leaning towards starting x number of 100 page+ authority sites.
First doing MNS and turning 'winners' into authority: I don't think this is necessary or even good. I think the site name would look spammy (three or 4 words). I would just do research and start with a 20k- 30k exact - probably a two-word name, with something catchy like 'zone.com' slapped behind the name. This way, I think you look 'authority' from Day 1, and your success in legit blog posting, etc. goes way up.
[edit] If I were doing massive MNS, then I would super-super-spin broad content and post to all of them (not using adsense in this model). I think that is what expertpeon (an expert but not peon) was talking about?
Comments?
lost lot of quality leads at our main office due to phones not working. Just getting back to work now, seems like I wont be getting much sleep for next few days 
