Is there a way to replace RDS Gateway with some sort of linux based proxy. I know there some ways to do it with ssh/port forwarding, but this is to replace a current RDS Gateway our users utilize for remote access (~300 users). I need to support multiple windows clients using their native RDP to connect to their windows desktops on campus, using some sort of linux proxy in between. 

From my searching, there are some solutions (xrdp,ssh proxy, port forwarding, etc) that sort of do what I need but they either aren't user friendly or they involve using multiple/non-standard ports. Before I give up my search and succumb to paying MS Licensing for RDS, is it currently possible to use linux to proxy RDP from windows using their native client?

[Multiple Remote Windows Clients] => [Linux proxy/gateway] => [Corporate Windows Desktops]