I'll give you guys a secret weapon: AdWords Editor. Use the keyword grouper tool to group common terms into ad groups.
With how little I have to make to be profitable, I don't research niches at all. I just throw keywords into campaigns and let it fly. I don't really keep track of how many keywords I use in a given niche, but to get keywords I just use AdWords Keyword Tool and export them to CSV.
Then I just create one ad group in adwords editor, paste all my new keywords in there (that are relevant to eachother), run the keyword grouper tool, and I get tons of ad groups created on-the-fly. I have some campaigns with a couple ad groups and a couple campaigns with 100-200 ad groups.
I haven't confirmed this yet, but I'm guessing that the QS will go up when you group your common terms into ad groups.