http://www.metalsdepot.com/index.phtml

I got a chunk of 3/8 aluminum one foot square and made my own table insert.
The 6 inches or so from the bit seems to be enough flat area to allow nice
raised panel work.

Table deflection vs size. I looked up some engineering formulas. If a
given weight deflects a beam .005" and you double the length of the beam,
the deflection goes up a factor 8 to 0.04. I.E. it is important to supply
support close to the weight as it is a 3rd power law.

Greg