I choose to build square frame legs since I felt this would offer the best
stability. And easy construction.
I started by laminating 2 2x4's together to make some 4x4's. These were cut
to size. The tops and bottoms were cut to about 1 inch short of the width of
the top. The legs where cut to be about 4 inches shorter then I wanted the
top of the bench to be. The bench ended up being about 3.5 inches thick.
 
     
After the pieces where cut to size I used large mortis and
tendon joints to hold the legs together. Here shows cutting the mortises in the
tops and bottoms.
 
And here the tendons for the legs.
 
Another shot of the mortis.
 
Nice tight fit.
 
Test fit of the legs.
 
I then laminated some 2x8's together to get cross supports.
I then cut mortis and tendons for these.
 
Dry test fit of frame.
 
After the legs where glued I put pegs of 1/4inch.
 
Test fitting top on, the clamps are because I had a large
twist in the top at this point.
 
After a lot of planing I finally got it to sit flat on legs.
 
A shot down top shows that it is flat (the gentle curve is
due to camera lens effect).