capri0mni | pricing advice, please.

Okay, so as some of you know, I've started writing custom fairy tales on commission (people ask me to write a story on a particular theme, or subject, or for a certain occasion, and I write an entirely new "fairy tale" to fit). When the story's complete, I send them a text of the story in email (or other form of PM), and a hardcopy through the post. I've been charging a flat fee of $35 (£19.41 or 28.55).

I strive to make my hardcopies neat, with a nicely proportioned font and all -- not too crowded, with nice margins. But they've not been anything special -- just loose pages, single-sided, on 20lb, all-purpose paper. Lately, I've been thinking that it might be nice, especially if I'm commissioned to write the story as a birthday present, or something, to give the option of having the hardcopy be printed in a more polished form ... "bind" it in one of those vinyl report covers, with a clip spine, and print it on heavier, 28lb paper (that's what Kinko's uses), so I could print the pages double-sided, and maybe even with color embellishments, and then charge extra, to cover the cost of the extra materials, and the extra labor involved.

So here's my question: How much would you be willing to pay for custom fairy tale (perhaps with a color design on the cover) that you could put on your bookshelf, and sit down and turn the pages?