woah woah woah.
you wont save any weight by swapping out the frame.
the reason the giants are the same weight, is the only real difference is the position of the pivots and the length of the levers.
there wont be much in it for any frame you could buy i dont think
you will be better off, getting another pair of wheels and or forks for your reign IMO.
the number 1 bike improvement anyone can make is tyres, get something light and fast and it will transform any bike.
i rode my Patriot 66 with a 38t ring last friday up afan, with race kings on rather than DH tyres, and it was a rocket.
if you want to spend some more money, wheels are your next buy. and then the fork if its something porky like a zocchi.
as a laaaady, i might gues you are less heavy on your wheels than your average gurt male oaf.
some light XC rims built properly should last you just as well, and make the bike loads better.