Custom Keylogger Needed Computer Knowledge Essential

We need a custom key logger to be build this must be able to record all keystrokes/key presses and it MUST be able to evade all or if not most detection methods. It also will need to unpack in a silent method unknown to the target i.e if the target opens an attachment it must then install itself and run silently without the target knowing what has happened. In the future we may require more advanced options such as screen shots /urls visited etc. However this is not a necessity but would be a great plus. Please do not contact or try to pass us any commercial key loggers/software as 99.9% of these have been flagged down by virus/key logger detection methods. Experience or past similar projects would be great! SERIOUS BIDDERS ONLY!!