I'd look at the Olympus XZ-1 or Panasonic LX-5. Both have fast lenses which really make a compact work for stock, in my opinion, by avoiding the need for higher ISO and allowing more motion stopping shutter speeds.
I own the Canon G12 and Panasonic GH2 and use both for stock, but the micro four thirds options are not pocketable unless you pick specific lenses. Don't get me wrong, I love my GH2 with 20mm pancake and slip it into a large coat pocket, but for stock I need some zoom ability.
Now that Panasonic has a power zoom pancake lens it might be truly small in size when combined with the GF3 or the new Olympus Pen Mini - but still has a slower max aperture (f/3.5-5.6). Something like the G12 is nicer to use than most P&S, but offers no image quality advantage over the much smaller Canon S95 or S100, and loses a stop on the lens aperture as well...
This is a recent upload with my Panasonic GH2, which is similar in quality to other recent m4/3s offerings:
Or this assignment entry:
This is a G12 shot:
The bottom line is that just about any larger sensor P&S will do if you just want it for moderate wide angle shots in outdoor conditions. Micro four thirds won't really give you much advantage, in my opinion, unless you start getting into lenses beyond what comes with the kit.
I didn't want to recommend a camera I hadn't used - but the Fuji X10 is very nice to use :) More versatile for stock than the X100, though image quality is lower. I'm finding the X10 does as nice a job as micro four thirds with the kit lenses.
No RAW support in Lightroom/Adobe yet, though... :(
I just recently purchased a canon G12 because of the control over shutter and aperture. I am pleased so far with he quality. It is small enough to travel with, I have been taking it everywhere I go and am having fun playing with it.
Nikon D90 with 18-105 mm, 35-80mm, 60mm micro and 18- 250 lenses.