You know the i-mate Ultimate specs inside out by now, although screen sizes and device dimensions may still be a bit of a blur - so, head over to
Todo Pocket PC and check out the informative spec sheets of all five Ultimate devices. In a nutshell, the 8150 and 9150 sport 2.6" touch screens, the 5150 and 6150 sport slightly larger 2.8" touch screens, and the 7150 adds another inch with a 3.8" touch screen - all in 262K-colour, VGA goodness.
Update: Size comparison figure added below.
From left, 5150 to 9150.