Just before the New Vandenburg Rebellion occured, the Star League had several advanced weapons research programs on Terra dedicated to the honing the bleeding edge of war technology.
The Cloudscythe LAM program was one of those programs closest to making it to the production lines. Fortunately for Kerensky, the design facilities were destroyed, along with all prototypes when Amaris struck.
Or so it was believed.

With the success of the 50 ton Phoenix Hawk LAM and the null-signature system equipped Exterminator headhunter mech, Star League planners envisioned a fusion design that would merge the strengths of both machines into a single deadly chassis capable of stealthy strike operations under any condition. The project was codenamed 'Cloudscythe'.
After reports came in of the Phoenix Hawk LAMs being too slow at times, the engineers installed a new XL engine in the Cloudscythe to boost its speed while keeping a weapons heavy attack profile.
And its weapons complement was indeed deadly. Armed with a variety of lasers and missiles, the Cloudscythe pilot can engage at ranges to his own liking, aided by the maneuverability of the LAM.
The centerpiece of the design, other than the LAM conversion equipment, was the null signature system. Capable of blending the mech into almost any environment, it could also work in space and atmosphere, an invaluable advantage in any aerospace dogfight. However, it is still liable to detection by radar and other sensors, even with a tighter profile under many sensory systems.
The project workers were reluctant to release the Cloudscythe for production before all the bugs were worked out. By the time they have ironed out all the kinks, Amaris carried out his betrayal.
The facility was destroyed, and the prototypes with them. However, in 3069, rebel troops on Terra uncovered hidden information that led them to a small depot in the Alps containing all the prototypes and the design plans for the Cloudscythe.
It was to prove a boon, not only to them, but also to the people of the Inner Sphere.

In 3069, guerilla forces on Terra opposed to the Word of Blake carried out a stunning raid with a full company of prototype Cloudscythes recovered from a hidden cache hidden in the Alps.
Using their unique advantages, they first sped along the ground in Air-Mech mode to avoid the Word of Blake's aircraft sensors, then just before coming into range of Blakist ground sensors, they changed into aerospace mode to carry out a devastating strafing attack against Word of Blake defense installations, setting the stage for the rest of the guerilla's ground forces to storm the Ural depot facilities and destroy the weapons of mass destruction the Blakists had amassed.
Without the Cloudscythe, it was likely such an attack to destroy the weapons would have failed, and the Blakists' jihad would have been very much deadlier.

The modern Cloudscythe, used by rebel forces on Terra, swapped out the old medium and small lasers for 2 extended range models, and upgraded the SRM launcher to a Streak type.

The remaining Cloudscythes are currently held by the Star League Defense Force on Terra, as the council debates whether to start the production of these stunningly effective LAMs.