No, such sites do not currently exist (or are still in "stealth mode").
That said, the idea of transmitting smells via the Internet is nothing new – in fact, DigiScents was a startup created 10 years ago to develop the "iSmell", a hardware device that could reproduce smells based on a data file transmitted via email, or embedded in a website.
It's entirely possible that one could license the iSmell IP, and embed similar data into dating profiles. Of course, the original iSmell was an output-only device – which means a second device (iSniff?) would be required to identify and codify the unique smell(s) of each site member.
Read more on this rather unusual startup, as well as a few other historical attempts at transmitting smells electronically here: