It's certainly a great idea and would be excellent for getting a leg up on opportunities near where you happen to be living at the moment. The difficulty in it is the chicken and egg dilemma and the initial non-concentrated userbase.

I only know of various expat community forums and sites which anyone can find with a Google search and a few subreddits (like /IWantOut).

Edit: I found this via Google http://www.digitalnomadcommunity.net/

I'm part of a paid, private online forum of 'digital nomads' (though everyone hates that term) or 'location-independent entrepreneurs' that also places much importance on solving entrepreneurial loneliness via in-person meetups etc. There are hundreds of members. You have to be doing something worthwhile to be accepted. It's called the Dynamite Circle.

I also have been looking for this and have found nothing free & compelling out there.

I'm considering building a platform for a self-organized digital nomad community. I am currently exploring ways to provide initial value to have it grow organically and would love to get other people's perspective.