As you can see from the posts above, you've already got some fine answers from the people behind E-ditor and E-Book HTML Compiler Pro.
I thought you might like to hear an answer from the people behind Web-Compiler and Neo-Book, too.!
So I asked them your questions, and got the following answers:
WEB-COMPILER:
"<< Can anyone out there help me find the ebook maker that allows me to do the above *and* allow the reader to advance from page to page using PGDN/PGUP instead of the mouse? >>
You can't normally do that in WebCompiler, because of course the page may be longer than a screen so people would probably want it to have it's normal effect.
However, you might be able to do it with JavaScript I suppose."
NEO-BOOK:
"a) Display web pages regardless of what browser you have
Provided that the user has some type of browser software installed (like
Netscape or IE), NeoBook can display a web page or html file using its
InternetLink command. For example:
InternetLink "C:\HomePage\awards.html"
InternetLink "http://www.neosoftware.com"
b) Demo version opens only a few times, and each time only for X minutes
You could probably use NeoBook's scripting language to do something like
this, but an easier method is to use a third party product called Armadillo.
This add-on allows you to limit the number of uses, and use passwords or
codes to unlock the program after a purchase.
c) Easily sell on it the web; password is automatically given to credit card
users; free e-mail addresses are rejected (to minimize fraud)
You would need to sign up with an online service (like digital river, etc.)
to process orders and credit cards over the net.
d) Edit-copy and print options can be disabled
NeoBook can prevent copy, paste and print for objects displayed within
NeoBook, but cannot control these functions for other programs like web
browsers.
>Can anyone out there help me find the ebook maker that allows me to do the
above *and* allow the >reader to advance from page to page using PGDN/PGUP
instead of the mouse?
NeoBook allows the PGUP and PGDN keys to be used to navigate through a
publication."