What to do during the Implementation phase

Once it's time to turn a prototype into a concrete, usable, and ready-for-release product, I find that the role of UXers quickly becomes idle. Developers tend to swat away any meddling once they put their fingers to the keyboard. Designers hold in their hands self-laminated designs that, in their eyes, are the immovable representations of our vision as a company. Project managers are now eager to cut the ribbon and push for development to complete as quickly as possible.

The problem is, until the next project begins, I've been finding myself twiddling my poor lil' UXing thumbs.

All the while a small set of problems arise: Developers create something that isn't quite how it was imagined by the team during our brainstorming session. Designers become frustrated when last-minute revisions muddy up their spotless layouts. Management is contemplating why such an involved process was needed to arrive at this point, proposing to trim down the design process next time while effectively overlooking the true source of this newfangled efficiency exhibited by the development team.

I'd like to intervene, but how? How do I prevent the implementation of the design thinking process from becoming a runaway train? and how can I supervise it efficiently without stepping on toes or breaking hearts?