Prepare for the Pitch: give us a look-see:
http://www.2much.net/
LiveCamNetwork is a complete site solution, not a script per se. You basically get three sites - the part the customer sees, your Administrator section, and the performer's chat & admin areas.
You don't need anything additional; if you have your own billing we can integrate that, but we also have a solution for you if you don't.
While we're working on a way for you to take it off site, the deep code currently isn't available; the program suite is a SaaS or software as a service - which has more advantages than disadvantages.
It depends how or what you want as modification. Maybe we should discuss?
We work with you on any server-side modifications you need, and otherwise you have full FTP customization access.
Call us or check us out: our packages are here
http://2much.net/cgi-bin/sign-up/pricing.pl , then dial 1-866-892-5122 (I'm extension 2)
:D