the Canon G3 is perfect. But for taking pictures of model tanks and trying to get professional results, forget it. The words cheap and professional results really don't go well together. You can get professional results with an inexpensive camera ($300-$500)but not a cheap camera (
Bouncing around the DPReview website (www.dpreview.com) I did find this camera:
It is within the $300-$500 range, has manual aperture with a 0cm amcro focusing distance (you can touch the model withthe lens and it will still be in focus) and you can still sneak it into a party and snap pics of drunks for later use.....
for models, I suggest:
When I was searching for my next camera a few years ago, My list of priorities included:
Manual aperture and shutter
Macro focus range of 0cm
I eventually bought a Sony H50:
The photos from this camera look like this:
These are all 1/48th sale Tamiya kits taken with the H50.
I hope this helps.