You should be able to do this yourself pretty easy, If I understand you correctly you want to stream a channel to another location over the internet? As long as you've got decent upstream that shouldn't be a problem. I'm not sure why you want the server box to output hdmi though, unless you mean you want it to output it via hdmi at your other location?
You could get away doing this with an old PC & a Raspberry Pi 2.
E.G. Server [Tvheadend] -> Internet -> Raspberry Pi 2 [which outputs at 1080p].
You would need to setup your server at location A [Install tvheadend secure it, the OS etc & open ports needed].
You could then setup a raspberry pi running a vanilla raspbian install with omxplayer at location B & setup a cron script at boot that automatically calls omxplayer [with the url of the stream from location A]. This script would obviously need to check the stream is still active and restart it if necessary.
- I'm pretty sure if you join the IRC channel [#hts on freenode] you'll get the help you need to setup something like this very easily.
You may also find someone to do this for you too.
HTH