Sell the plans really cheap. Don't allow copying (to keep rights), but don't enforce anything. This will contribute making them popular. A low price will also mean many just buy the plans to browse them without having committed to building. Or just to pick ideas from them.
Then incorporate some parts that are not very easy to make for everyone. Make these parts yourself, and sell them together with plans. These should of course be parts that needs to be somewhat complex because this makes it a better product. One obvious example is brackets that makes the product more rigid. From what I see on the net, that is the most repeated shortcut. Obvious examples are mills where little or no concern is made about what happens when cutting forces and rapid move of masses are applied to the construction. If you make a design that incorporate well thought out distribution of forces and masses, I'll be one of your customers rather than going through the tedious process of designing one myself.
I take your comments as a bait for starting a joint project here on CNCzone.com? OK, I take the bait with hook line and sinker if the project is a small CNC mill.
With the wealth of resources here, this could be both fun and educating.
VacPress, you obviously are a master 3D draftsman. And I've seen other postings around here that shows great knowledge ranging from demanding users to analytic problem solvers.
So isn't it just opening a forum on Open Source CNC Mill then? :-)
The software can be found over at
www.linuxcnc.org, but there is no hardware.