As far as I know, the Wiremold 600B [500/700] bender is still available, although they can be hard to find. I see them come up for sale on eBay every once in a while.
I had to special order one myself about 10-years ago for a job with a lot of #500, but haven’t really used it much since then.
IMO, it’s expensive for what it is, which is basically just a short radius shoe that is similar to the old Klein/Benfield short radius bender, just with a modified square hook. Actually, if you have one of the old Klein two groove 1/2" and 3/4" short radius benders, I found that it will also work on 500 and 700 wiremold. It’s still allowed to be used for this purpose, since the radius of bends for surface metal raceways isn’t addressed in NEC 386.
I find that you can make longer radius bends with a standard EMT bender lined with an old T-shirt that will look decent, but it leaves a slightly bigger gap between the wall and the back of the raceway. You just have to go slow so you don’t get wrinkles or dogleg twists in the wiremold.
These suppliers also say they have it for sale:
bender1 bender2 bender3 
