I managed to connect to Hyper-V consoles via FreeRDP, which means that now it's possible to connect to Hyper-V from Linux, Mac OS X and Windows (including Server Core / Hyper-V server), without needing vmconnect / RSAT.
In order to ease thing up I also added a Powershell cmdlet. Here's the blog post about it:
http://www.cloudbase.it/using-freerdp-to-connect-to-the-hyper-v-console/
It would be great if somebody could help in testing it and providing feedback! :-)
Thanks!