I understand OP was referring to something more along the lines of escorts or full-service sex work, but camming -is- a form of sex work; anything that involves profiting from sexuality even if it doesn't involve actual contact is still sex work.
Back on topic, the answer is yes. I knew a girl who worked for Pixel Vixens. Bat shit in fucking sane so I don't speak to her anymore. She's married so she didn't do what OP describes, but apparently she knows other sex workers including some of the other PV girls who have sold themselves at cons.
On a mildly related note, there was also this asshole>Guy who hung around old con group was a sad lonely neckbeard who literally lived in his family's basement surrounded by Rei merch and used his student loans irresponsibly>First con I went to, he bought badges for three girls in the room that flashed their tits>I refused, but he nagged me regularly afterwards offering to give me free shit for sexual gratitude, even just photos>Nearly every woman he's interacted with at a con has accepted his requests, so he never learned to back off>The following year he buys a netbook for him mom and she doesn't want it>New girl shows up in the room and he gives her the netbook in exchange for her getting naked and talking to him for 15mins>Apparently offered one of my other friends an iphone in exchange for something similar