These seemingly fragile legs are getting very popular, they come in many different options- 2 pin, 3 pin and interesting angles, but the all have one thing in common-they look amazing. These legs are not cheap, a set of 4 of 28″ can come up to around £70 on Ebay, depending on the finish (rough, paint etc), but it is well worth the money.
I think if you find a local metal working shop, you can order anything you like, but bear in mind that the legs need to suit the construction- think of the purpose and the total weight of the furniture before you decide which legs to buy.
The other part of the design is (in my case) wood-all kinds of tops, boards, finishes will marry these hairpin legs in the way that will turn some heads around. My favourite combination is some bulky design, something that makes almost an awkward looking piece, like the legs do not fit into the whole idea, but after taking a good look-it all makes sense and it is unique.
I am currently working on one of those projects, will post the pictures within few days.