MQ2AutoSize - Shrinks anyone in range down to minimum allowed size.
They will revert back to normal when they move out of range. These effects are CLIENT SIDE ONLY!
Code: 
/autosize Toggles AutoSizing on/off.
/autosizeall Toggles AutoSizeing for the whole zone on/off.
/autosize -range # Sets the range for AutoSize. 
 
MQ2AutoSize.ini - Sample Configuration and description

[Config]
Range=50 
Size=2 
PetSize=1
AutoSize=on
AutoSizeAll=off
ShrinkPets=on

Range: is the radius in feet that will be shrunk.
Size: is the size they will be shrunk down to.
AutoSize: will shrink everyone within "Range".
AutoSizeAll: will shrink everyone in zone upon zone-in.
ShrinkPets: Toggle to shrink pets along with PC's.