B&Q have 1/3rd sheet worktables (4ft by 2ft 8in or 1.2m x 0.80m) for £25.
The trestles are made from 42mm x 18mm spruce, which makes them very light and useful for other boat building tasks:

The table is 19 lengths of 42mm x 18mm glued together:

I doubt we could make one for that price. Get 2 and you could handle full sheets.
The Xmas quiz is how to attach the table to the trestles for heavy duty work. Countersunk 6mm bolts where my first idea......
-Paul