Difficulty isn't a problem. It's fairly easy to do. The issue comes with building it in anticipation for something that not many people have shown any interest in. For me, I have to evaluate whether or not building a mod would be worth the time and effort in doing. Every minute I spend building something has a cost value associated with it. When I build mass-produced mods, the sale of such a mod is what makes up for the time. If I spend 2-3 hours building a mod and no one buys it, then that is 2-3 hours of wasted time. This is the sole reason why I do not build a lot of mass-produced mods. Rather, about 99% of what I do is custom mods. They are built as needed or requested so that I am not wasting time on things that people are not interested in.