As you zoom in with the digital zoom, you blow up the noise level proportionaly to the amount of zoom. The additional noise becomes less appearnt with higher meagpixel cameras, but it's still there.
I would look for an 8X or 10X lense, and full manual control, as well as good macro focusing if you wnat close ups like Shamus is famous for. For less expensive models that cover that criteria, check out the Olympus C-7xx series (except the C-720), the Minolta Z1 or Z2, and the Fuji finepix series. If you are using it for modeling and not general purpose, the 10X lense is less important.
I use this site to compare:
http://www.steves-digicams.com/hardware_reviews.html
For macro, the closer the foucus, the better. Within a couple of inches or less is good. Again, higher megapixel cameras can make up for a deficiency in this area, because you can electronically blow it up once on the computer.
As far as megapixels, if you have a good lense (and for me that also measn good macro), 3 is enough, but more is better.
I chose hte Minolta Z1, although it does not macro as close as the C-740, I figured I could crop it on the PC with 3 megapixels and have a clear image. I tested the theory with this photo and proved it to be correct. More than you asked

but I hope it helps.