We used tickets somewhat and we are self hosting through a nginx proxy in order to log the http activity and proxy over https. The ticketing has markdown support. We use a custom theme, not for tickets but for the whole repo. Fossil tickets are only used internally, we use osticket regular ticketing.

There is also a service for hosting fossil repos called Chisel, but it's nowhere near as useful as Github.

http://chiselapp.com/

Thanks!