I recently purchased a King Arms V2 M120 complete mechbox, and I love it.
Combined with a Modify hopup unit and the Modify hybrid inner barrel, I'm shooting great.
Quick drop in and go for the mechbox and then all you are left to do, is play with the hopup.
Got it all here:
One option for you.
As for the Metal body, post up a WTB ad in the WTB section.