In responce to a question posted on Curbly, here is how to build an inexpensive but still very modern bed.
You can achieve a nice low bed with a very simple design. You could simply build a square frame that rests on the floor at the desired height by using 8x8. This would give you a nice 8 inch rise off the floor you could even go with 8x6 or 8x4 if you want real low. Cut the length to be a bit smaller than the mattress so you can create a nice overhang which is very modern and adds that bit of design to the piece. Once you have built the frame you need to create the platform for the bed to rest on, a nice piece of 3/4 ply would work. Make sure to cut it to fit the mattress for a nice tight fit. Then to finish the nice clean look, take some finishing pieces and build a very low frame around the ply so the mattress will sit inside the frame and finish off the rough edge of the ply.
This will create a very nice looking bed. You can expand on this design to create sitting platforms on the sides or foot of the bed as well. You can even build drawers that go under then bed for additional storage. You can then paint or stain the bed to match anything in the room.