Vanessa's pair isn't by Dolce Vita, it's from Urban Outfitters a couple of months ago. I have this pair of sandals and it didn't cost more than $20. U.O.com obviously doesn't carry it anymore but I am 99% sure that VH's pair is from U.O.
Vanessa has had these either a year or over now, they are the Dolce Vita Aegean Faux Snake Toe Ring Thong Sandal in Black Snakeskin. They ran out around last July, but perhaps they will bring them out again in time for summer this year, or a similar style.
UO does sell Dolce Vita though, maybe they copied them because they were so popular?