I read somewhere that pectin from lemon peels is even more concentrated than that with apple. It's a very similar process so I hope you try it and write about it!
I am envious that you have citrus trees out the wazoo - that would be so amazing. I pay over a dollar per lemon for organic. They come from overseas so they aren't exactly fresh either.
Oh wow. That is expensive! We have oranges, lemons, limes and grapefruits that we've noticed so far...most are extremely sour. I've got to look into making pectin with them!!