Hiya, I am a VB.NET/C# developer that would be willing to help you out with your RAT. Currently I have one built with polymorphic code and a UAC bypass that I can customize for you. Alot of your requirements can be met by the remote command line interface, even if they might not be functions per-se. If you would like buttons to do these tasks I can implement them fairly easily.
Thanks for reading over my bid details!