Hi Mumuney,
There are several products that use FreeSWITCH for its core, and then offer that product as a platform - although 2600hz is the only ones that springs to mind.
You might be able to talk directly with one of these companies (say ITSPTec or Cudatel) to see if they would offer a bespoke managed platform for you.
Speaking personally, I spent quite a while reviewing different FreeSWITCH GUI/API platforms and they were all lacking in one area or another.
Currently myself and a few other developers are building a platform that sits on top of FreeSWITCH, which then provides all the typical features you'd expect to see in a wholesale/multi-tenant platform, accessible via a sane API and web interface - however this is several months away from completion, open sourcing it will inevitably take longer, and the first release would only be considered a 'stable beta'.
Hope this helps!
Cal