3.625 by 5.375 by 1.375 and10 oz = RIOT
2.430 by 4.020 by 0.780 inches and 6.5 ounces = IPOD

The RIOT is 50% wider, 25% taller, 100% thicker, and 60% heavier.

I think that once you reach a small enough dimension that the unit will fit comfortably in a shirt pocket (and the Riot certainly qualifies), there is no significant advantage to making it smaller.

Suppose you could shrink it down to the size of a matchbook? Would there be some advantage to being able to carry a dozen of them at one time in your pocket?

tanstaafl.