care less what the trend is and care more about what works.

Yes, niche sites still work... and a 50-100 page site is very authoritative IMO. (hell lot better than my 1page sites that still rank lol).

Do you proper keyword research and come out with very low competitive keywords but have enough traffic. But an authority site on that keyword. 3 or 5 pages are ok and give quality blog posts. Engage in proper seo and you would begin to rank. The trend is, google is making it difficult to rank for main niche keywords.

Both would work, but if you ARE gonna write 50-100 articles, make it once large site than. You'll save cash in the domain names. It'll also be easier to organize.

A site with 50 - 100 pages would not be considered a thin affilaite site. That sounds quite beefy to me. I think bouth work. As long as you build a themed site around whatever niche you choose.

Fifty to one hundred pages can absolutely function as an authority site. Just provide good content. Most of my sites are only slightly larger and I get consistent returning traffic, which is a key indicator that your site has gained authority with visitors.

Go for it, my site currently have only about 30-40 pages and have consistent traffic and sales as well.

Like others have pointed out a site with 50-100 sites is as good as if not itself an authority site. Google puts emphasis on fresh content so it may be a good idea to spread over posting such that you are posting everyday or every few days.

Geesh! 50 - 100 pages sounds like "authority" to me....especially since they are going to be niche specific. Google loves to see relevant content on sites so I think you will be viewed as authority.

Yep, 50-100 is definitely authority. Once you have that many pages though, I don't see why you wouldn't want to add a few more if you find the good keywords for it.