What features would you want to be integrated to the script related to proxies. Our fellow team is coming up with a new proxy model consuming low resources.
I personally prefer everything in the Glype script, its pretty much the perfect script. Very low on consumption, uses the cURL model (like many new proxy scripts do), supports pretty much anything you want to do with it. If you really want to go further, (and if you're going to offer the script free of charge), i don't think there is one out there that allows an admin to charge for use of proxy (IE: Ads free, being able to enable/disable certain features for free/paid members). Hope that helps.
I got an advantage using Glype I understand what your talking about. We are more leading towards all in application of a proxy script. Not add ons but only one total script