So I'm fairly cautious when it comes to making and selling kits, mostly in that I'm worried about people thinking I have copied or stolen their idea and monopolised on it.
Its this reason that currently the only kit I sell is a derivative of a mates design that I improved on and sold with his blessing.
What I would like to know from peeps here is, when is it ok, and when isn't it, to make a kit?
A real world example for me at the moment was a idea I had for turning your arduino into a e-pet by making a shield that has a screen, buttons and speaker. I also had plans to make a stand alone kit that rolled in the arduino for compact-ness. But it hit a bump when I couldn't find a distributor for the screens. Now I have, but at the same time this: http://logicalzero.com/gamby/ started being sold on tindie (where I also sell my kits), its pretty much similar. I would still like to make then sell my kit, but i'm worried I will be seen to be copying (even though I designed and planned the kit months before I ever saw the gamby) this kit maker. I don't want to ask for their blessing to sell my own, as that to me will look much more like I'm trying to 'rip them off'.
It seems its hard to have an idea for kits and products that haven't been thought of or made before as either just a project or a kit, but if at the time of conception or design you don't know about previous peoples work, would you worry about being called out to have plagiarized their work/idea?