Vayable customers about to meet their charming homeless tour guide (Photo: blog.vayable.com)

If you’ve ever hoped of touring Paris’s sewer system in the dead of night accompanied by a lovely French homeless man, then you and I have a slightly different definitions of the word "vacation." But for more adventurous travelers, Vayable might be able to make your unorthodox dreams come true. The San Francisco-based travel start-up announced a few new features today, including concierge and improved international payment services.

Y Combinator-backed Vayable, which launched in April 2011 and opened an office in New York a few months later, offers over 2,500 unique travel experiences to its users in 600 cities around the world. Some special souls have used the site to spend the night on San Francisco’s former prison island –Alcatraz – while others have gone on tours of the Tenderloin neighborhood in San Francisco guided by a homeless man.

But now you can demand more through company's concierge service, which allows users to request experiences not currently offered through Vayable.com. Think of them as your fairy godmother, except you still have to pay and they won’t turn your carriage into a pumpkin. (Though you could try and request it.)

“We were finding that there were a lot of people who wanted more nuanced and customized experiences,” Jamie Wong, co-founder and CEO of Vayable told Betabeat, noting that the concierge service will allow users “greater flexibility,” especially because they can name their own price. Apparently there are a lot of “nuanced” Vayable users, because Ms. Wong said Vayable has already received hundreds of requests through the service.

The three-member staff also launched an improved international payment method, meaning Vayable can convert users’ payment into over 35 local currencies and can pay guides directly through their local bank. They will also refund you in case, for some reason, your homeless guide bales out on the whole sewage tour thing.

Vayable is currently a member of the summer 2012 Y Combinator class, and Ms. Wong said it's doubling revenue month-over-month since joining the program.

In a few weeks, they are hoping to announce some initiatives related to campaigning and elections, and in August, they will also be hosting a Startup Crawl in San Francisco to allow customers to visit the offices of Airbnb, Dropbox and others. Maybe they can then cart everyone over to Alcatraz and see if any of the techies can figure out how to escape the island, Birdman-style.