If I'm the first 'bigger girl' on there there's proberly a market for it!
Unusual logic, you could equally say as there are none on there then there is no market.
What I would suggest, and I don't know if this is a daft suggestion or not, but why not book one of the girls and see what she is like. I am not sure if you are bisexual but it seems most Escorts are so am assuming you are.
Either way you will see the girls are nothing to be intimidated by, or conversely you can see first hand of what you need to aspire to.
I have a feeling it will just be a case of a little knowledge of the finer things, wines, classical music business goings on and also the right demeanour and posture that these high class girls will have.