Wish I saw this earlier. I just built a website solely for this purpose. The website is umerefer.com.
It's geared toward travelers...lots of credit card referral opportunities, but I'm adding other stuff (airbnb referrals, booking.com). A user recommended adding google express, so I did that.
It's a bit challenging getting the word out...I'm reaching out to moderators on various sites to see if i can mention the website. Trying to respect the rules and etiquette.
I think the site is cool because filters can be used to immediately connect a user with an Airbnb referral with another user who has a Booking.com referral, and so on. I find it more efficient than using the forums.
Anyway, I'd appreciate hearing your thoughts on the site, and if you think it has some value, mentioning it to other people.