Here's another thought. Given that she's a sex worker and her job is essentially getting paid to have sex (in a video), it might not be totally out of left field to offer her a sum (let's say, the same amount she makes from selling one of those fan videos), only in this case, you'd be the fan, and there wouldn't be any raffle involved.
So basically, you'd film a video with her just like any other fan, but you've paid directly for the spot. Then she makes some extra cash by selling the video. Really, it's not that much different from what she's already doing. The only real difference would be the absence of the raffle.
Given that she's around 500 subscribers, at $15 per video, I'd reckon she's pulling in, at a generous estimate, somewhere between 7k and 10k. The one with Keiran, which was public prepaid, that's what she earned. So if you've got 10k to spare and you want to spend it on a roll in the hay with her, she might be interested.
Anyway, many porn stars (or sex workers, as you aptly put it) also work in high-end escorting. It's just another aspect of their job. If this chick has been fucking with random fans just because they won a raffle, what reason would she have to turn down a good sum of money to do the same with you?