RE: largest electric?
Look into the Miniature Aircraft ION-X. It's a .90 size electric based on the MA Fury Extreme/Tempest helis, that has been around for a few years, before the boom in large electrics. Though they are showing out of stock, Heliproz has a listing for it. Located [link=http://www.heliproz.com/prodinfo.asp?number=166900]here.[/link] The ION-X is $1,380 for the heli, motor, and ESC. The killer is the batteries. It takes 8-10 Cell LiPO or NiCD/NiMH batteries with 28-32 cells. They are set up for 2 batteries per flight, 1 mounted on each side of the main frame. Not a cheap proposition.
With the current battery and motor technology, I wouldn't doubt that you'll see much larger electrics (in place of turbines or gasoline motors in some birds), especially in the scale arena.