Someone called 'creamsugar' had this to say about a 3DS revision...
The new model:
Wider viewing angle
2 analog sticks
As big as DSi LL or Vita
He also tweeted this (May 17), which may contribute to a double the resolution rumor:
800 * 480 ?
*This could mean double the base resolution of 3DS(400*240) or a doubling of the vertical resolution in 3D*
He is apparently a respectable source, and he knew about MonHunTriG a year before announcement. Take it with a grain of salt, but this may be a hint towards a 3DS XL...