I wanted a corner banquette in my eat in kitchen,but couldn't find anything I really liked.  I decided to look into making one myself, after doing some research I chose to use the Ikea Kallax Shelving/Cubbie.  The dimensions work really well for the space I have in my kitchen too.    I chose to buiild my base first, so I could get accurate measurements to purchase your materials.  Here are the materials you will need to make your cushion.  Plywood- cut to size of your bench (Home Depot and Lowes can cut to size for free) I used 1/2 inch  Foam- I used 2 inch (buy at any craft store, check for sales and coupons, foam isn't cheap)  Quiters Batting- this is nice because it will hold together the foam and wood, and cover the bottom of the wood so you don't scratch your bench.  Fabric- I was able to cover both benches with 2 yards of 54" wide fabric (my bench is 57.75" X 15.5")  Tools:  Staple Gun  Hammer- for any staples that don't go in all the way  Flat Head...
Random reviews of freebies I get to test. Also some DIY instructionals of my creations.