Well, Spook, GeForce Experience 1.8 was released already beginning december with this feature:
"With the release of GeForce Experience 1.8, we’ve implemented many of the community’s most requested enhancements. First and foremost, Windows 7 users can now save up to 20 minutes of Shadow Mode footage, just like Windows 8 users, and Windows 7 Manual Mode is no longer restricted to a single 3.8GB file – footage is now recorded continually across multiple files until the moment you run out of HDD or SSD space."
source:
GeForce Experience 1.8: Introducing Adjustable Optimal Playable Settings & Significant ShadowPlay Updates | GeForce
And GeForce Experience 2.1 got released beginning of this month:
Release Highlights
ShadowPlay
Adds in-game framerate counter
Shadow Mode can now be used with desktop capture
Adds push-to-talk functionality
Extends capture resolution up to 2560 x 1600
Improved audio synchronization when editing with Adobe Premier
Improved Twitch streaming stability
ShadowPlay on/off state now persists across self-update
General
Improves self-update installation speed
Various bug fixes