Reverse Gravity

Now up for sale is this week's Behind the Spells release--Reverse Gravity! Grab it here: http://www.rpgnow.com/product_info.php?products_id=6525

I've been thinking, off and on, about doing a series similar to BtS in that I take an area of the core rules and expand on them with fluff and variant crunch. And while there are a number of things to choose from, the problem lies in making such a pdf series accessible to both DMs and players. In theory, more players that are consumers in the marketplace than DMs although I'm not sure if that holds true for the pdf market. With the undenied success of BtS (at least in my opinion), I'm wondering if I can capitalize on the same type of business angle. Ronin Arts has already done a good job of this in publishing pdfs for mundane items, magical components, etc. but I think there's still something that can be exploited. The question is, will I want to write it if I can think of a topic? Not weekly, certainly, but monthly perhaps.