I'm playing in a D20 Modern/Future campaign where the GM is being pleasantly flexible about Prestige classes. I have what has thus far been a Dedicated character who acts as the group medic. I'd like to branch out the character a little more and don't think any of the Prestige classes that the GM has been able to find are a good match.
Are there guidelines somewhere for creating your own Prestige classes, in terms of making them work with game balance and so on?
Thanks in advance ... .