I don't think you charge too much for your time/work. I don't believe anyone should have to work for free.
That's why I paid the original amount when I got my first Empeg too, because after reading these boards for a bit I had come to the conclusion that those things really did cost that much to produce. I don't regret it one bit because I believe it was totally worth it.
I'm sure it's the same with your lenses. The only thing is, I don't really have a need for it now. That may change in the future when/if I have the button hack done. Since I don't know IF this will ever happen I also don't know if I'll even have the need for a Neon Red lense.
I can only hope that you'll still be making them when that time comes, or when stocks become low and you decide to call it quits you'll notify us of this here on the boards. (but I'm pretty sure you will)