Affiliate Marketing Secrets

In Tim Ferriss’s prescription for creating a business in the 4 Hour Workweek, he advises finding a market first, then making a product for them.
I have followed the steps in the book and identified a few niches I could market to. For each niche I have found several small trade magazines. So far, so good.
The problem is, after contacting the ad directors at a few of these magazines (to ask for back issues and their current rate card), they all hit me with a barrage of questions like “what’s your product URL?” and “what is your product?”
This is a catch-22, because I want to validate the magazine before I come up with a product idea, let alone launch a website.
What do I tell these folks? Has anyone here created a muse successfully following Ferriss’s steps in the 4 Hour Workweek? What’s the best way to ask for this information when you DON’T EVEN HAVE A PRODUCT ?
Thanks in advance!

I have a product idea that I am considering selling through Clickbank. I don’t expect it to be just a HUGE seller – it’s in a craft niche and I know that’s not one of the better ones, but I know a lot about this niche and can create a great product. There doesn’t seem to be anything comparable on CB.
But I thought this would be a great opportunity to ‘get my feet wet’ in this area of IM.
What I am wondering about is if a product has a gravity of 10 (that’s just an arbitrary number), what does that represent? I’m just trying to get an idea of about how many sales are possible, although I know that no one can really predict this.
My other question is how do affiliates find the product to promote it? The reason that I want to go through Clickbanks.net is so that I can focus on the product and affiliates can focus on the promotion, right? So, will I still need to go out and find affiliates?

I want to create a product but its affiliated with a company. Example but not my product idea: Say i want to make a pair of Nike sneakers but since NIKE already made sneakers id have to use there company logo for this product. So how do i start up my product and pitch my idea. I feel my product can deff sell in the market but im 25 years old with only $1000 to my name.