Well, either of the BlackBerries would be more suitable as a "pocket" device than the Treos; they're both lighter and thinner than any of the Treo models.
However, to really consider them as pocketable devices, you need to more fully define what you mean by a pocket
I think I would find either the 7130e or 8703e as a bit large for carrying in business/casual trouser pockets, front or back. Either would fit in a shirt pocket, but would certainly affect the line of shirt; although they're lighter than Treos, they're sill not what I would consider "featherweight." You'd have more options with painter's or cargo pants, but they may not be appropriate for the environment in which you'll spend much of your time.
The only suitable (pun unintentional) pocket for most occasions would be an inside pocket in a suit or sport jacket.
I briefly considered the 7130e when I decided to switch to a BlackBerry last year, but disliked the SureType keyboard. I didn't find the difference in size between the two significant enough to put up with SureType. I'm very happy with my 8703e (although there are still a number of features I wish it had, the primary being voice dial).