You know the Panasonic FZ20 has a macro function and image stablizer?
It is ideal for the purpose you described and at about half the cost of
a DSLR, it has a Leica lens and very good quality images.

Many point-and-shoot digital cameras have more than adequate macro
capabilities for the pictures you need to take. If you want a DSLR
also for other uses, practically all DSLRs now on the market are more
than adequate. The choice depends on the additional uses you want to
make of your camera.

With a DSLR, probably you should get also a macro lens (even though
your present needs may not exceed 1:10 to 1:5 magnification ratios).
However, you may start without one first, and decide later if you
really need it.

You must invest some additional money and time in a macro setup,
because this will affect the quality of pictures much more than your
choice of camera and lens. You are going to need a tripod and head for
the camera (and/or a repro stand if you will be taking pictures very
often), a couple of incandescent lamps (for your use, 75-100W cheap
construction lamps with an aluminum reflector and a clamp are fully
adequate, no need to buy expensive photo floods), reflector panels
(white foam-core and/or kitchen-sink aluminized plastic mats are
fine), diffusing panels (translucent white shower curtain on a light
frame) a stand for holding a paper background (if you are not shooting
only vertically downward; make-your-own is best) and some form of
supports for the lamps (make your own, or use cheap music stands).
Forget about repro stands with built-in lights, these are good only
for illuminating flat documents evenly, but they don't let you place
the lights freely. Search the web for information on how to arrange
lights and reflectors (search for e.g. studio photography). Your setup
and equipment will be smaller than most professional ones, but the
same general rules apply. Preferably, set up a table to use only for
the macro setup if you need it often, so you will not have to unpack
and repack it every time.