Ikea has some that look like this. But they're probably going to fall apart within a few months.

This one is cushy and low, and pretty similar. It's from CB2.

http://www.cb2.com/plush-natural-bed/f7666

They have a couple of different styles there. I saw something similar at West Elm in LA, in store. But I don't see it online. So, that's another idea.

Good luck, hope that helps a bit!

PS Sarah, there's a couple of colors available on that CB2 bed. It comes in a gray color as well. I'm sure you could figure that out from looking around, but I wanted to mention it since the picture you posted is closer to a gray color. :)

BluDot Furniture is a great source. http://www.bludot.com/modern-bedroom-furniture/modern-beds.html

Viesso has something similar

The Tate bed at Crate & Barrel is beautiful. A friend has it and loves it.

World Market has some less expensive upholstered platform beds, although they're pictured with boxsprings. Read the product descriptions to see which ones come with slats.

It's hard to tell from the pictures in the link below, but Dixiefoam has a really cool "PlatFoam" bed made of heavy duty foam. You can add a rounded headboard so that it's all one piece; I had one years ago covered in charcoal gray that I loved. Quite reasonable too! Also, their mattresses are amazing-- I think mine has been in the family for 15 years and it's as comfortable as ever.

http://dixiefoam.com/foundations.htm

Bonaldo has lots of options. www.bonaldo.it

ikea made a GREAT low profile bed a few years ago, only down fall was that it weighs a ton. it's too bad they discontinued it because it was only around 500$bucks. hopefully they will come out with a lighter version.
http://i.ushipcdn.com/resize.php?path=%2Fstatic%2Fd0a0c7ab-07e5-4e54-8.jpg&w=270&h=210

We just bought this exact bed from Ashley Furniture for $410, it's super low and such nice quality!! We were thinking of making our own, but a king size platform bed at that price is too great to pass up.

http://www.beckerfurnitureworld.com/Item.aspx?ItemID=-2083015740&ItemNum=B702-78%2b76

I have the IKEA bed- as shown here in green- and I LOVE it!!

http://www.apartmenttherapy.com/ikea-2009-catalog-second-lookt-58587

I got it on craigslist second hand, so I don't know if you can still get it. Good luck with whatever you get!

It is not as padded as the version you like but I have wanted one of these for awhile now.

http://www.bludot.com/modern-bedroom-furniture/modern-beds/hush-queen-bed.html

I would second the cb2 bed recommendation, but I will tell you in person it is VERY low, like essentiallly the same thing as a mattress on the floor low. It wasn't the feel I was looking for, but it was a very good-looking bed.
Most of cb2's beds were very low and didn't require box springs.

For mine, I bought the really cheap Ikea Fjellse pine bed frame, and cut the legs down to 2" off the floor. I also cut the headboard off but you could keep it and upholster it if you want, so that it looks like the photo you like.

But then, I like DIY and modifying everything!

How about our beautiful Portia bed? http://www.styleinform.com/catalog/Category/Beds/portia-bed-queen-stonehouse-grey/367

I was looking for an upholstered platform bed myself a few years ago but my search was more specific. We have a (king) Tempur-Pedic and the warranty is void if you don't use a "firm, solid-surface, non-spring foundation or adjustable bed base that is structurally capable of supporting the weight". We needed a low/platform bed that could also hold/fit their low profile foundation. Anyway, after over a year of searching we got a great deal on a Coaster bed I stumbled upon online and priced checked to death before snagging it for $470 at Mercantilla (I'd never heard of them until then and I haven't bought anything there since). It's still going strong. Amazon also carried it, search for: Contemporary Eastern Standard King Size Platform Bed.

Room and Board has several options, but we went with the Wyatt high headboard bed. Love, love love it! http://www.roomandboard.com/rnb/m/product/detail.do?articleNumber=100924&an=0_100924&qa=0_WYATT_VIEW_COLORWAYS|G15&productGroup=3641