Dave,
Do you need such a 'top dog' table top? The extruded aluminum, is it flat on top or ribbed? I had a ribbed top one when I was using my table saw extension wing, and I did not like it for certain applications, smooth and flat was better.
There are a lot of ready made tops in the 2' x 3' range, or make your own custom size tops. You probably can do a lot better than $500
http://www.mlcswoodworking.com/shops...utertable.html http://www.rockler.com/product.cfm?p...%20table%20top http://www.hartvilletool.com/product/10942
or solid phenolic
http://www.jointech.com/routertops.htm
If you really want to spend a lot of money (with no appreciable gain, unless you are doing A LOT of cabinetry)
http://grizzly.com/products/Router-Table/G0528