The cushions are 2" fairly dense foam purchased from a local foam shop, cut to fit exactly. We found some cool patterned fabric, and with some basic fiberboard from Home Depot cut to the same dimensions, we stapled the fabric underneath.
The cubbies now have some simple baskets in them for storage, mostly used for drawing and craft material for our kids.
Total cost was roughly $350. The Trofast units were about $90 each, the foam was $120, the fabric was only around $20, plus we bought high quality paint from Benjamin Moore and few other incidentals.
Step 1: Get the Trofast Units From Your Local Ikea.
Initially we thought about using a few of the units that already sit flat for wall or floor storage, like these:
but when we went to Ikea and took some measurements, we ended up with two of these instead:
My guess is that any of these would work out, though you may not be able to mix and match if the heights and depths don't align.
Step 2: Lay Them Out and Cut As Needed
You can buy extra shelves for these. Because these Trofasts are intended to be upright, the add-on shelves just come with the little flat things that they rest on, so I had to use some screws to secure them. The shelves also have notched areas where the mounts are intended to go: I just left these as is. They aren't that noticable once you paint and put the baskets into the cubbies.
Step 3: Sand, Prime, Paint, Etc.
Step 4: Make the Cushions
I then went to Home Depot and just bought a big sheet of thin fiberboard there, and had them cut pieces to the same dimensions as the foam. I think it was probably $10 total. I used board thats actually similar to the backing that comes with the Trofast units. Unfortunately those boards were not quite the right dimensions. While you are there, buy a can of Scotchgard as well to treat the fabric. Also, get yourself a staple gun if you don't have one already.
We found some cool fabric at a local fabric shop that matched some other colors of the kitchen. Unfortunately, its probably not the most durable, so if you have kids or are clumsy, pick something that cand stand up to some wear.
Making the cushions was pretty straightforward. We laid out the fabric on the floor, upside down. Lay the foam on it, and then lay the board down, matching everything up evenly. Start at a corner and pull the fabric up tight and start stapling. It was a little bit of trial and error, and we got better as we went along, but in general it worked out pretty well. The hardest parts are the corners. You might try making a few cuts on the areas underneath to get a nice fold and less overlap.
Step 5: Put It All Together!
We got these foam baskets at Target for pretty cheap. They fit the space well, they are low enough that you can see whats in them without pulling them all the way out. Depending on what you are looking for storage wise, though, there are a lot of possibilities, and depending on how handy you are you can probably find some other options.