this was a design that came to me and smacked me in the face so i ran with it and this is what i came up with...
the table top is supported by a central pole.
the string evens out the load on the table top.
the higher the tension the more rigid the table...
provided the central pole can support the tension.

Step 1: Materials ( Not Shown)

i made the table before i thought about making an instructable to go with it.
plywood
2 inch wood screws
para cord (or other strong string, or cable)
17x eye screws
1 inch pvc pipe
old satalite dish( if you dont have one of these just use some plywood)
small table top(also can be substituted with plywood)

TOOLS
drill
jig saw
circular saw
hole saw

Step 2: Drill Holes

measure the center of your table top and drill a hole with your 1 inch hole saw
and insert your pipe...
must be a tight fit or your table will be wobbly.

Step 3: Attach Plywood to Dish

you can skip this step if you are just using a piece of plywood as your base.
just drill a hole 3/4 of the way through your wood and insert the pipe into it.

to keep the plywood and the pvc pipe in place i just used a single large bolt and placed the pipe over it.

Step 4: Attach Eye Screws

place eye screws at the corners and the midpoint on the sides.
(illustrated below)

Step 5: String the Eyescrews

string the screws like so...
tie it of like in the second picture

Step 6: Adding Tension

hold the table top level and begin adding tension to the string evenly around the table.
pluck the strings all the way around and if you hear the same high note throughout all of the strings you've done it right.