You certainly can create a font using your own set of symbols. That's pretty much what a dingbat font is. When making a font, the designer decides which symbol to put in the A position, which to put in the 3 position, etc, and which positions to not include in the font.
You might find this useful:
http://rapidshare.com/files/413591301/XXDWXX.rar
This is an archive of freeware fonts from Michael Lee, Josh Dixon, et al from Omega Design. They specialize in creating fonts of alien languages from science fiction movies and television shows. What they did and how they did it may be helpful to you.
~bito
But if I make the font myself, am I allowed to post it on DaFont.com?
~Dark
Edited on Aug 18, 2010 at 17:29 by xXDarkWarriorXx
All times are CEST. The time is now 22:16